According to the different requirements of each course, different credits are given, and the total number of different credits in each professional course is stipulated as the total credit for students' graduation. The distribution of credits taken in each semester is uneven. Take a four-year university as an example. The first and second grades are mainly based on basic courses, and more credit courses need to be taken each semester. Take professional courses in the third and fourth grades, with less credits per semester. The United States began to implement the credit system in the 1970s, and now most universities in the United States have implemented the credit system. The calculation method of credits is not uniform, so the total academic score is not uniform. Some universities in the United States stipulate to study 120 credits within four years, some universities stipulate to study 360 credits, and some universities stipulate to study more than 500 credits. Short-term universities such as two-year community colleges also implement the credit system, and the total credits for graduation are equivalent to the total credits for the first two years of four-year universities. After World War II, Japan implemented American higher education system, and all universities also implemented credit system. According to the unified regulations of the Ministry of Education, Culture, Sports, Science and Technology, a four-year university can only graduate with a total of at least 124 credits. Its calculation method generally takes 30 class hours as 1 credit. Only a few universities in Britain implement the credit system, which is called the curriculum unit system. A course unit is equivalent to 60 ~ 70 hours of teaching or 150 hours of experimental class, while the courses in the third academic year are calculated by points, and the learning weight of compulsory courses and elective courses should not be less than 20 points. French universities do not adopt the American-style credit system, but the equivalent unit system. Generally, you are required to complete the compulsory courses in Unit 16 and the elective courses in Unit 4 before you can graduate. The university of west Germany adopts the weekly hours system, and the total number of four-year weekly hours is 203 ~ 2 10 hours. Universities in the Soviet Union and some countries in Eastern Europe do not adopt the credit system, but the academic year system. From the 1930s to the early 1950s, universities in China used the American-style credit system. In the early 1950s, Soviet universities adopted the academic year credit system. At the end of 1970s, some universities tried out the Chinese academic year credit system to meet the needs of the development of modern science and technology.