Objective: To analyze the association between sleep chronotype and suicidal psychological behaviors among middle school students, so as to provide a scientific basis for the prevention and control of middle school students suicide. Methods: In October 2021 and November 2022, a multistage cluster sampling method was used to conduct baseline and followup surveys in Shenyang, Zhengzhou, Nanchang, and Taiyuan cities in China, and a total of 6 656 middle and high school students were included as the research subjects. The Chisquare test was used to analyze the groups differences, and generalized estimating equation was used to analyze the associations between middle school students sleep chronotype and suicide ideation, suicide plan and suicide attempt, and the grade stratification was carried out. Results: Baseline detection of suicide ideation, suicide plan, and suicide attempt were 26.3%, 12.6%, and 5.3%, respectively, with followup rates of 21.0%, 10.0%, and 4.8% for each, and varied significantly by gender, academic stress, smoking or alcohol use, and anxiety or depressive symptoms among middle school students (χ2=11.93-880.20, P<0.05). After adjusting for gender, academic stress, physical activity, smoking, alcohol use, anxiety and depressive symptoms, generalized estimating equations showed that compared with the morning sleep chronotype, the OR(95%CI) for suicide ideation, suicide plan and suicide attempt were 1.61(1.36-1.89), 1.66(1.35-2.05) and 1.41(1.06-1.88) among evening chronotype students, and were higher among junior 1.78(1.39-2.27), 2.00(1.48-2.69) and senior middle school students 1.84(1.44-2.35), 1.67(1.20-2.33) (P<0.05). Conclusion There is a positive association between evening sleep chronotype and middle school students suicidal psychological behavior, and improving sleep chronotype may be one of the effective measures to prevent middle school students suicide.