Objective To investigate the status and influencing factors of mental health services in primary and secondary schools in Shanghai, so as to provide evidence for training professional mental health teachers and delivering mental health services to children and adolescents effectively. Methods Totally 422 mental health teachers from 14 districts of Shanghai were investigated with a self-designed questionnaire on mental health services in primary and secondary schools. Pearson Chi-square test and Student’s tt test were used to compare the differences in sohool mental health services and influencing factors among mental health teachers with different educational backgrounds, and a structural equation model was constructed to analyze the influencing factors of students’ access to mental health services. Results The major of mental health teachers were mainly applied psychology (n＝124, 29.38%), education (n＝117, 27.73%), and developmental and educational psychology (n＝65, 15.40%). The top 3 mental health problems for students were social, interpersonal or family problems, anxiety, stress or school phobia, and adjustment issues. The organizations that had signed agreements or cooperated with school to provide mental health services were primarily the district mental health centers (n＝376, 89.10%), community health centers (n＝155, 36.73%) and local hospitals (n＝106, 25.12%). The proportions or scores of mental health teachers with master’s degree were significantly higher than those with bachelor’s degree for school mental health services, prevention and early intervention programs, data collection, and influencing factors of students’ access to mental health services (all P＜0.05). The need for mental health services (n＝328, 77.73%) and the number of students served (n＝314, 74.41%) were increased, while the funds for mental health services (n＝212, 50.24%) and the number of school mental health staff (n＝226, 53.55%) remained unchanged in the past 3 years. A structural equation model with 3 dimensions of school, family and society was constructed for influencing factors of students’ access to mental health services (χ²/df＝2.708, root mean square error of approximation＝0.064, normalized fitting index＝0.947, goodness-of-fit index＝0.946, adjusted goodness of fit index＝0.912, comparing fitting index＝0.965, relative fitting index＝0.926, Tucker-Lewis index＝0.952, increasing fitting index＝0.966, root mean square residual＝0.046). Conclusion Mental health services in primary and secondary schools in Shanghai has achieved remarkable progress. Post-employment training for full-time mental health teachers needs to be strengthened. The supply of school mental health resources should be guaranteed from multiple pathways, such as coordination of school, family and society, and medicine-education alliance. Special funds for mental health should be guaranteed.