Using data from the second wave of Busan Education Longitudinal Survey(BELS), the study analyzed the influence of parents’ school activity participation on general high school students’ academic achievement and provided the implications of policy for activating parents’ school activity participation. The school activity participation of parents of general high school students consisted of school activity participation in parent level and school activity participation in school level. The variables of the parent level include parents’ socioeconomic status, parents’ educational support, parent-child relationship, number of the parents’ school activity participation, and parents’ school satisfaction, and the variables of the school level include the number of person parents are monitoring, number of parents doing the monitoring, parents’ relationship with principal or community, and parents’ relationship with teacher or community. The main results are as follows: First, the parents’ socioeconomic status, parent-child relationship, and the number of the parents’ school activity participation influenced general high school students’ academic achievement positively in parent level. Second, the extent of the parents’ monitoring influenced general high school students’ academic achievement positively in school level. Based on the results, the political implications and suggestions were discussed.