Objective: The study aimed to explore the relationship between childhood maltreatment (CM) and the Big Five personality traits of middle school students, so as to provide scientific evidence for promoting the healthy development of middle school students personality. Methods: A total of 5 724 middle school students from Xuancheng, Hefei and Huaibei of Anhui Province were selected by using a multi stage stratified cluster sampling method to conduct a questionnaire survey, including demographic characteristics, CM experience and Big Five personality traits. Linear regression analysis and canonical correlation analysis were used to explore the associations between CM and the Big Five personality traits. Results: Physical abuse, emotional abuse, sexual abuse, physical neglect, and emotional neglect of middle school students were significantly associated with conscientiousness ( β = -1.71 --2.55) and neuroticism ( β =1.93-3.87) personality traits( P <0.05). Except physical abuse, all other types of CM were significantly associated with extraversion ( β =-1.04--2.32) and agreeableness ( β =-1.07--1.37) personality traits( P <0.05), and only sexual abuse was associated with openness personality trait( β=-0.70, P <0.05). Except for openness personality trait, the relationship between the number of CM experience and the personality traits of middle school students was statistically significant; there was a dose response relationship between the number of CM experiences and the scores of personality traits each dimension( P < 0.05). In the canonical correlation analysis, the canonical correlation coefficient was -0.375( P <0.05). CM experiences were mainly reflected by emotional abuse, emotional neglect and physical neglect (canonical load coefficient was 0.556-0.951). The Big Five personality traits were mainly reflected by neuroticism, conscientiousness and extraversion (canonical load coefficient was -0.702 -0.639). Conclusion There is a correlation between CM and the personality traits of middle school students, and prevention of CM is of great significance for promoting the healthy development of middle school students personality.