To explore how the personality of junior high school students affects their Internet addictive behaviors and to explore the causes of Internet addiction among junior high school students from a more comprehensive perspective by using negative life events as mediating variables. 254 junior high school students in Jilin university were surveyed by using Five -factor Personality Questionnaire for Middle School Students; Adolescent Self-rating Life Events Check List and Internet addiction tendencies. The research conclusions are as follows: (1) In the personality of junior high school students, centricity, agreeableness, prudence and openness, have significant negative predictive effects on Internet addiction. The emotional factors in the personality traits of junior high school students had a significant positive predictive effect on Internet addiction; (2)Negative life events on Internet addiction have a significant positive prediction function; (3) Negative life events had a full mediation effect between extraversion, emotionality and Internet addiction tendency. Negative life events had a partial mediation effect between agreeableness, caution and Internet addiction.