Objective: To explore the current status and associated factors of bullying behavior among middle school students in Shanghai, so as to provide a reference basis for carrying out bullying intervention work. Methods: From May to June 2021, a stratified cluster sampling method was used to select 19 000 middle school students from 63 schools in 16 districts of Shanghai, and the Shanghai Youth Health Risk Behavior Survey Questionnaire was used to conduct an anonymous questionnaire survey of enrolled students. Chi square test and binary Logistic regression analysis were employed to investigate the associated factors of bullying among middle school students. Results: The prevalence of bullying behaviors in Shanghai was 15.5%, with males and junior high school students exhibiting the higher reporting rate(19.5%,17.2%). And malicious teasing or name calling had the highest reported rate at 9.4%. The results of binary Logistic regression analysis showed that fighting ( OR =5.02), attempting to smoke ( OR =3.22), having a feeling of sadness and hopelessness ( OR =2.50) and getting drunk( OR =1.72) were positively associated with bullying behavior among middle school students. Fighting ( OR =3.83-8.97), attempting to smoke ( OR =2.92-5.52), having a feeling of sadness and hopelessness ( OR =2.40-4.34), and getting drunk ( OR =1.66-2.34) were positively correlated with 6 forms of bullying (malicious teasing or name calling, intentionally damaging someone else s belongings, deliberately excluding someone from activities or isolating someone, threatening or intimidating others, hitting, kicking, or pushing someone, and verbally harassing or attacking someone online) ( P <0.05). Conclusions Bullying behavior of middle school students in Shanghai primarily presents as verbal harassment. In the future, greater attention should be directed towards bullies, and it should recognize potential hazards promptly and implement precise intervention measures.