The aim of this present study was to evaluate the effectiveness of a child sexual abuse (CSA) prevention curriculum toward children and to compare the knowledge gains between children who were taught by teachers and their parents. Four hundred and eighty-four school-age children recruited from one primary school in Beijing, China, were randomly assigned to a CSA prevention program administered by teachers or their parents or to a wait-list control group. The findings reveal that children in the teacher education group demonstrated the highest level of CSA prevention knowledge and skills, followed by the parent education group, while children in the control group showed the least improvements. The knowledge and skills gains were retained at a 12-week follow-up. The present study shows that Chinese school-age children can benefit from CSA prevention program with increased knowledge and skills of personal safety. School-based CSA prevention education should be improved and implemented in other regions of China.