There is no uniform regulation on the number of years of graduation, and the requirements of different schools may be different. Generally speaking, graduate enrollment units will formulate corresponding enrollment policies and requirements according to their own conditions and enrollment plans.

The requirements for postgraduate enrollment in some universities are as follows:

1. Undergraduate graduation time: Most colleges and universities stipulate that the undergraduate graduation time should not exceed two or three years in principle when recruiting graduate students. There are also a few colleges and universities that allow candidates who have graduated for a long time to apply for the exam.

2. Work experience: Some colleges require candidates who apply for a master's degree to have work experience. Usually, you are required to work for no more than a certain number of years (such as 3 years or 5 years), otherwise you can't apply.

3. Other requirements: Some colleges and universities have other special requirements, such as requiring candidates to have certain scientific research experience, paper publishing experience and so on.

In short, there may be differences in postgraduate enrollment policies and requirements of different universities. If you want to apply for graduate students, I suggest you know the enrollment policies and requirements of relevant universities in advance, so as to better arrange your study and work plan.