What age is Liu Cixin’s science fiction works suitable for?

High school students and above can understand it.

Because there is a lot of scientific knowledge in his works, children below high school may not be able to understand it.

In fact, his works are very suitable for adults to read. They cover astronomy, geography, science, human ethics, morality and religion, and are not made up randomly. Liu's thoughts are very profound and logical. I still like him better.