Later, Sun Yat-sen explained why it was this sentence.

The development process of the Three People's Principles is divided into two stages, namely, the old Three People's Principles and the new Three People's Principles. This is the precious spiritual heritage of the people of China.

The old Three People's Principles reflected the basic social contradictions during the old democratic revolution in China, and summarized the three major struggle tasks put forward by the objective historical process. 1894 (20th year of Guangxu reign of Qing Dynasty), Sun Yat-sen established the Zhong Xing Society in Honolulu. The first oath of joining the Party organized by the bourgeois revolutionary democrats was: "expel the Tatars, restore China and establish a coalition government". This oath, together with the contents of the Hui Constitution, has become a short expression of nationalism and civil rights. For the first time, the program "Zhong Xing Hui" put forward the requirement of democratic nation-building. The following year, when Sun Yat-sen fled abroad after the abortion of the Guangzhou Uprising, he seriously studied the bourgeois social and political theory and made an on-the-spot investigation of the capitalist social system. "Those who only know that the country is rich and strong, and the civil rights are developed like European powers, have still failed to reach the land of bliss. So there are people with lofty ideals and social revolutionary movements in Europe. I think once and for all, the people's livelihood should be adopted to solve the problems of nationality and civil rights at the same time, and the idea of the Three People's Principles will be completed. " In the later revolutionary practice, the Three People's Principles have been enriched and developed. In the platform of the League, the Three People's Principles are completely expressed in four sentences: "Expulsion of Tatars, Restoration of China, Establishment of the Republic of China, and Equal Distribution of Power".

Nationalism is the first battle flag unveiled by Sun Yat-sen.. It reflects the complex ethnic contradictions in modern China society-both the contradiction between imperialism and the Chinese nation, and the contradiction between the Qing ruling group headed by Manchu nobles and the Han nationality and other ethnic minorities. Imperialism and the Qing ruling group are increasingly colluding.

One of the main contents of nationalism is "anti-Manchu". "Expulsion of Tatars and Restoration of China" has always been the battle slogan of bourgeois revolutionary democrats in the late Qing Dynasty. This is not only because the Qing Dynasty was a feudal autocratic regime dominated by Manchu nobles, but also because it has become a "foreigner's court". This is the reason why the slogan of "anti-Manchu" has extensive mobilization significance. Avoiding the bad luck of China being divided and ruled by * * and striving for national independence and liberation is another main content of nationalism. In the People's Daily article, Sun Yat-sen listed "forced by foreign countries" and "forbidden by foreign countries" as the basic reasons of nationalism. "Non-revolution cannot save us from death", but the revolution must "overthrow the Manchu government first", and the significance of nationalism against imperialist oppression is contained here.

Civil rights are the core of the Three People's Principles. It reflects another major contradiction in modern China society, namely, the contradiction between feudalism and the masses of the people. The basic contents of democracy are: exposing and criticizing feudal absolutism, pointing out that the feudal social and political system deprived human rights, so it is by no means "unbearable for equal citizens"; It is necessary to overthrow the feudal monarchy by means of "national revolution" and replace it with "democratic constitutionalism" to end the serious state of "being confused by the poison of Millennium autocracy" In line with the "transformation" of this "state system", the division of political system also constitutes an important content of civil rights.

People's Livelihood is Sun Yat-sen's "social revolution" program, and the task it hopes to solve is the modernization of China, that is, to develop the capitalist economy and make China become rich from poverty; At the same time, it also contains the content of caring for the life and welfare of working people, as well as the criticism of capitalist social and economic ulcers and the resulting "sympathy for socialism." Sun Yat-sen summed up the main contents of people's livelihood as two major issues: land and capital. "Land equalization system"-"State-owned land" is Sun Yat-sen's land plan. The main content is "when improving the social and economic organization, the land price in the world is approved." Its existing land price still belongs to the original owner, and the price increase of social improvement and progress after the revolution belongs to the state and is enjoyed by the people. Sun Yat-sen believes that the implementation of this plan can prevent monopoly, make the public richer and promote "social development". On the issue of capital, Sun Yat-sen affirmed that "China needs industrialism". He believes that the modernization of China is an inevitable trend of history, and the book Industrial Plan is a grand blueprint for developing social economy. He summarized the way to develop social economy as "controlling capital" and developing "national socialism", that is, "exclusive large industries that cannot be entrusted to individuals" (such as railways, electricity and water conservancy) are all owned by the state, because this can not only "prevent the abuse of capitalist monopoly" but also "combine the resources of the whole country". People's livelihood is essentially a plan to maximize the development of capitalism, although it is painted with the color of subjective socialism.

The Three People's Principles has its historical limitations, mainly manifested in the lack of clear and thorough anti-imperialist and anti-feudal content. However, it critically inherited the positive contents of the peasant war and the Reform Movement, and borrowed from western democratic ideological materials, and became a relatively complete program of democratic revolution in modern China. The Three People's Principles reflected the principal contradiction in the semi-colonial and semi-feudal society, expressed the people's desire for independence, democracy and prosperity, and marked the beginning of the old democratic revolution in a more complete sense, which played a significant positive role under the historical conditions at that time.

China's revolutionary course entered the stage of new democracy. With the help of China's * * * production party and the international proletariat, Sun Yat-sen "conformed to the world trend and met the needs of the masses", established three major policies of uniting with Russia, uniting with * * * and assisting the peasants and workers, and developed the old Three People's Principles into the new Three People's Principles. In nationalism, the topic of anti-imperialism stands out: "For most people, the struggle for national liberation is nothing more than anti-imperialism"; Civil rights further exposed the tyranny of feudal warlords and bureaucrats, criticized the bourgeois social and political system, praised the "people's dictatorship" of Soviet countries, and reiterated the principle of "sovereignty belongs to the people". People's livelihood emphasizes the view that "land to the tiller" and expounds the view that "private capital cannot manipulate people's livelihood". The new Three People's Principles is the development of the old Three People's Principles, which reflects the new historical characteristics, shows the progress of bourgeois revolutionary Democrats in the new revolutionary stage, and becomes the political and ideological basis of the first state-to-state cooperation.

At present, the famous slogan of "Three People's Principles for the Unification of China" in Kinmen is far from the slogan of "One Country, Two Systems for the Unification of China" on the other side of Xiamen.