Imperial academy was first established in the period of Emperor Wu of the Western Han Dynasty. Emperor Wu of the Han Dynasty adopted Dong Zhongshu's suggestion of "developing imperial academy, setting up teachers to educate people all over the world", and set up imperial academy in Chang 'an to teach Confucian classics. At first, there were only five doctors in imperial academy (Yi, Shi, Shu, Li and Chunqiu), and there were 50 doctoral disciples. At the end of the Western Han Dynasty, it increased to 3,000, and by the time of Wang Mang, the number of Imperial College students had increased to more than 10000. These people were hired on the basis of their achievements after passing the exam.
All previous dynasties in imperial academy paid attention to examinations, but the forms and methods of examinations were different. In order to cultivate "wise men" and "handsome men", imperial academy in the Han Dynasty "tried his best to ask questions". The examination period is roughly one year in the Western Han Dynasty and two years in the Eastern Han Dynasty. The examination methods include "oral test", "strategy test" and "setting subjects and shooting strategy". The so-called "shooting strategy" means that doctors compile classic questions into strategies and divide them into subjects such as A and B according to the difficulty level, and candidates randomly choose questions to answer. This method is similar to the modern lottery proposition self-answer examination method. When the audience with the emperor, the examination method is fixed, the number of places to be admitted is unlimited, and different official positions are awarded according to the amount of classics. This practice of paying attention to the examination of classes and trying to draft talents has broken the system of respecting the world and cronyism, which is of positive significance for selecting talents. At the beginning of the Han Dynasty, more than two thousand years ago, the experience of imperial academy examination was created, which was also rare in the history of world education at that time. The examination of central official schools in past dynasties can be regarded as the inheritance and development of imperial academy's examination method in Han Dynasty.
The prosperity of imperial academy in Han Dynasty was closely related to the talent selection system at that time. Too many students will become officials directly after passing the exam, and even if they fail, they will have the opportunity to make up the exam. In addition, Thai students still have the opportunity to be officials in the central government after returning to their places. At that time, there was an opportunity to recommend talents to the Central Committee once a year, and most of the candidates were from imperial academy. Therefore, after Emperor Wu of the Han Dynasty, most officials in the DPRK were educated. Entering imperial academy, passing the exam and becoming an official became the dream of Han students. There are many students in imperial academy. After all, only a few can become officials. Some people go to school in their teens, with white hair and no job, and their lives are down and out. As a result, the imperial court awarded official positions to students over 60 years old several times, which was considered as a mighty imperial favor.