Objective To investigate the influencing factors of mental health in primary school students from Grade 3 to Grade 6 in Zhongshan city,in order to provide basis for children's mental health care service in the future. Methods A random cluster sampling method was used.And a total of 2 236 students of Grade 3 to Grade 6 from eight primary schools in Zhongshan city were enrolled in this study from March to June in 2016.The Mental Health Test (MHT) was used to investigate the mental health status,and the influencing factors were investigated with the self-compiled general information table. Results The positive rate of mental health problems was 10.38% (232/2 236).Multivariate Logistic regression model showed that the risk factors included maternal bad mood during pregnancy(OR=3.18),birth asphyxia(OR=2.39),primary family discipline (doting,mixed)(OR=2.11,1.66),academic performance (good,average,poor)(OR=1.57,1.97,3.53).And protective factors were fathers' occupation (civil service or technical personnel)(OR=0.34) and lower grades (OR=0.54)with statistically significant differences (P<0.05). Conclusions The mental health status of senior primary school students in Zhongshan city is not optimistic,and individual,family and school factors influence the mental health.So the relevant department should pay more attention to these factors