September 1. According to the inquiry of China's Ministry of Education, as for ordinary high schools, it is usually in early September of each year. The specific dates may vary from region to region, but they are all around September 1. This also means that the entrance time of freshmen in senior high school in 2023 should be 1 in September 2023. However, because the opening time of schools in the whole country is not stipulated by the state, the specific opening time still depends on the regulations of your high school.