OBJECTIVE To find out the prevalence of bullying behaviors among urban middle school students in China. METHODS An anonymous questionnaire survey was conducted among middle school students selected by multiply stage cluster random sampling in 18 provinces in China. 187 328 self-administration questionnaires were finished by students from grade 7 to 12 in urban middle school (male, 86,472; female, 91,106), in which 177,578 were valid. RESULTS Bullying was common in urban middle school students in China. Multiple bullying behavior also existed. About 66.1% of boys and 48.8% of girls suffered from one or more kinds of bullying; 8.1% of boys and 2.9% of girls suffered from four or more kinds of bullying. Boys were more likely to be bullied than girls. Malicious teasing was the most common bullying behavior(43.2%), followed by sexual bullying behavior (27.0%). In addition to malicious teasing and sexual bullying, the prevalence of other types of bullying declined when the grade was increasing. Residential students were more likely to be maliciously teased, excluded or isolated and sexual bullied than non-residential students. Students from single-parent or recomposed-families wer more likely to be bullied than other students. Male and ordinary school students,students living with single or step-parents were more likely to suffer multiple bullying behaviors at the same time. CONCLUSIONS The suggesting among students was associated with personal, familiar and social factors, mobilize more social forces and comprehensive actions to be taken to prevent bullying among students.