Abstract: To investigate the effect of high-intensity interval training (HIIT) on cardiopulmonary fitness and body metabolism in adult patients with mental disorders. By searching the published literatures in Chinese and English databases, randomized controlled trials of HIIT intervention in adult mental disorders were collected. Data extraction and bias assessment of the included literature were conducted, and RevMan5.3 software was used for meta-analysis. Results: 8 studies were included, including 393 patients. All 8 articles had bias risk with different degrees. Concerning the safety and feasibility results, the incidence of HIIT adverse events was low at 3.92% and the dropout rate of patients was 26.96%. As for the cardiopulmonary fitness results, the maximal oxygen uptake (VO₂max) was significantly higher than that before HIIT intervention, but the effect of respiratory exchange rate (RER) was not significant. In the results of the metabolic outcomes, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly reduced within the normal range. Fasting blood glucose (FBG), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), body index (BMI) and waist circumference were not influenced. Compared with MICT, there is no significant difference in VO₂max level. Conclusion: Current studies show that HIIT is safe and feasible for adult patients with mental disorders, and can partially improve their cardiopulmonary fitness and body metabolism There is no significant difference in the improvement of cardiopulmonary fitness compared with MICT.