Objective To have knowledge about the characteristic of loneliness in left-behind junior middle school student and its relation with personality so as to provide a reference for schools to conduct mental health education.Method A survey of 250 left-behind junior middle school students was conducted by means of a questionnaire survey and the result was statistically analyzed.Results Differences in overall average scores on dimension of peer status and loneliness between male and female junior middle school students left behind were statistically significant（p<0.05）;overall scores on loneliness had negative correlations with extraversion

agreeableness and openness of personality

and extraversion of personality had a significant negative correlation with loneliness and other four dimensions;in the multiple regression of personality and loneliness

extraversion and neuroticism entered the regression equation.Extraversion and neuroticism could jointly predict the 24.9% variation of loneliness while extraversion could explain 17.8% variation of loneliness.Conclusion Loneliness among left-behind junior middle school students varies by sex

and extraversion and neuroticism are direct predictors of loneliness.