Three years. Official website, Jinan Education Bureau, inquired that primary education is compulsory for 6 years. During this six-year period, student status will be retained by the school. The retention period of primary school students is 3 years. Students who do not re-enter school within 3 years after graduating from primary school will be disqualified. Therefore, the time for primary school students in Jinan to repeat the grade is 3 years.