Objective: To analyze the relationship between school bullying and parent child separation of left behind children, and to provide a theoretical basis for preventing and controlling school bullying of left behind children. Methods: A total of 4 945 children aged 7 to 18 in Shangrao City were selected by stratified cluster random sampling to complete the Chinese version of the School Bullying Experience Questionnaire(C-SBEQ), and the differences of school bullying between left behind and non left behind children were compared. The parent child separation data of 1 791 left behind children was obtained by self designed questionnaire, and the influence of parent child separation characteristics on school bullying of left behind children was analyzed by binary Logistic regression. Results: The rates of school bullying, bully victimization and perpetration of left behind children were 21.3%, 18.3% and 3.0% respectively, which were higher than those of non left behind children(15.4%, 12.7%, 2.7%). And there were statistical significance in the detection rates of school bullying among left behind children in different schooling stages( χ 2=9.82, P < 0.05), the detection rates ranked as follows:21.4% in primary school, 18.9% in junior high school and 14.7% in senior high school. The rate of bullying perpetration among left behind children was significantly higher in boys (4.8%) than in girls (1.0%)( χ 2= 14.69, P <0.05). The rate bully victimization among former left behind children (children with left behind experience) in the younger than 7 years group ( 20.3 %) was higher than that in the older than 7 years group(13.4%)( χ 2=4.79, P =0.03). There was no significant differences in the detection rate of bullying perpetration among the left behind children with different parent child separation experiences ( P >0.05). Control schooling stages, Logistic regression analysis showed that taking former school age left behind children as reference, bully victimization risk of former pre school left behind children was 1.64 times( OR=1.64, 95%CI= 1.04 -2.59, P <0.05). Conclusion School bullying of left behind children is more severce than that of non left behind children. Early occurrence of parent child separation is associated with higher risk of bullying victimization among left behind children.