Objective To explore male juvenile delinquents' personality traits and the relationship with personality and family environment,parenting style,and to provide evidence for juvenile delinquences prevention,education and reform. Methods A total of 218 male juvenile delinquents and 211 middle school boy students were surveyed with Eysenck Personality Questionnaire,Family Environment Scale and Egna Minnen av Barndoms Uppforstran scale. Results The levels of N and P in EPQ of juvenile delinquents were higher than those of middle school boy students with statistical differences (P<0.001).The levels of E,P and N of delinquents' were correlated with their family environment and parenting style in several dimensions(r=-0.136～-0.417,0.149~0.374).Family active recreation predicted E positively.Mother's emotional warmth and family cohesion predicted N negatively,and family conflict,father's severe punishment,father's rejection predicted N positively.Mother's over protection and interference,family conflict,mother's favoring subjects,father's rejection predicted P positively(P<0.05 or <0.01). Conclusion Juvenile delinquents are highly neurotic and psychotic in personality,and the family environment,parenting style have specific influence on their personality.