Is it necessary to participate in electronic competitions if I major in electronic information engineering take the postgraduate entrance examination?

If you participate in the electronic competition, it means that your understanding of the major is in-depth enough. This is not necessary for the postgraduate entrance examination. However, having an electronic competition certificate will give you extra points and may allow you to be admitted under special conditions, but generally, applicants with electronic competition award certificates will be admitted. Work units will rush to get you. It's easy to find a job and the salary is high (not much worse than a graduate student), so you won't even take the postgraduate entrance examination.