In addition to full-time education in ordinary colleges and universities, there are four kinds of academic qualifications recognized by the state, followed by adult college entrance examination, open education in RTVU, online education and self-taught examination.

Among them, the adult college entrance examination is what people usually call correspondence. Correspondence education is very useful, which can be used to test qualification certificates, civil servants, promotion and salary increase. Especially undergraduate education, can also be used as the basis for postgraduate entrance examination and examination of civil servants.

Correspondence is a form of academic qualifications and a kind of adult college entrance examination. Commonly known as "a university without walls", it is a kind of national education series. The state recognizes academic qualifications and is admitted by taking exams organized by the state. The main links of correspondence teaching include self-study, face-to-face teaching, homework, answering questions, experiment, practice, assessment, graduation design and defense.

Adult college entrance examination is divided into three levels: junior college entrance examination (hereinafter referred to as junior college entrance examination), senior college entrance examination (hereinafter referred to as senior high school entrance examination) and senior high school entrance examination (hereinafter referred to as senior high school entrance examination).