Objective: To explore the effect of painting therapy on middle school students’ mental health and its influencing factors by taking the randomized controlled trials (RCT) as the analysis object. Methods: More than 10 domestic and foreign databases, such as CNKI, Wanfang, VIP, Web of Science, PubMed, Scoupes, MEDLINE, APA psyclnfo, were searched, and 735 original literatures were obtained. After screening, 28 literatures were included. Finally, 182 extracted data were analyzed by stata17.0. Results: (1) Due to the large heterogeneity (Q=1967.81, p<0.001, I2=90.80), the random effect model was used to combine the effect sizes. The results showed that the effect sizes of painting therapy was a positive large effect (g=0.90). Sensitivity analysis showed that the pooled estimate was relatively robust. (2) Painting therapy had a positive effect on four kinds of outcomes: emotion (g=1.61) , cognition (g=0.78) , behavior (g=0.65) and self (g=0.88) , and there was a significant difference among them (Q=20.38, p<0.001); The intervention on self-esteem (g=0.76) , anxiety (g=1.18) , depression (g=1.29) and aggression (g=0.69) also had positive effects, but there was no difference among the four (Q=3.476, p=0.324). (3) Painting therapy has a positive effect on the Ordinary participants (g=0.67) , subjects with psychological problems (g=1.13) and physiological diseases (g=0.59) , and there was a significant difference among the three effects (Q=14.556, p=0.001). (4) Both domestic (g=1.14) and foreign research (g=0.70) on painting therapy have positive effects, and the former is greater than the latter (Q=15.60, p<0.001). (5) The time could not significantly predict the intervention effect (B=0.003, t=0.37, p=0.713). Conclusion: The painting therapy has a positive effect on middle school students’ mental health. Future research can focus on the promoting effect of painting therapy on the positive mental quality of middle school students.