Objective: To learn the influencing factors for self-violent thoughts and behaviors among the ninth-grade students in Jiangbei District of Ningbo, so as to provide the basis for carrying out psychological intervention. Methods: The ninth-grade students in a junior high school each of the six streets ( towns ) in Jiangbei District were recruited by multi-stage cluster sampling method from October to November 2018. A self-designed questionnaire was used to investigate the general information, life style, psychological condition, self-violent thoughts and behaviors in the latest year. Multivariate logistic regression model was used to analyze the influencing factors for self-violent thoughts and behaviors. Results: A total of 1 300 questionnaires were issued and 1 238 valid ones were recovered, with an effective rate of 95.23%. The prevalence rates of self-violent thoughts and behaviors among the ninth-grade students were 16.88% and 8.48%. TheResults of the multivariate logistic regression analysis showed that abnormal marital status of parents ( OR=2.074, 95%CI: 1.139-3.775 ) , no moderate physical activity ( OR=1.764, 95%CI: 1.101-2.826 ) , sleeping less than 8 hours ( OR=1.858, 95%CI: 1.273-2.712 ) , alcohol consumption ( OR=2.108, 95%CI: 1.448-3.070 ) , sense of despair ( OR=6.397, 95%CI: 4.195-9.757 ) , sense of anxiety ( OR=4.094, 95%CI: 2.725-6.151 ) , sense of loneliness ( OR=1.879, 95%CI: 1.241-2.854 ) , and cyber-bullying ( OR=5.155, 95%CI: 2.780-9.556 ) were risk factors for self-violent thoughts; not living with parents ( OR=2.057, 95%CI: 1.021-4.145 ) , alcohol consumption ( OR=1.756, 95%CI: 1.074-2.872 ) , sense of despair ( OR=7.197, 95%CI: 4.365-11.864 ) , sense of anxiety ( OR=5.832, 95%CI: 3.276-10.382 ) , fighting ( OR=2.272, 95%CI: 1.219-4.232 ) and physical bullying ( OR=3.462, 95%CI: 1.135-10.558 ) were risk factors for self-violent behaviors. Conclusion Drinking, family relationship, bullying, and mental health problems such as sense of despair and anxiety were associated with the self-violent thoughts and behaviors of ninth-grade students.