Abstract: Objective To describe the status of subjective well-being among left-behind students in a city of Jiangxi province and to explore the relationship between family functioning and subjective well-being.Methods Totally 2 330 students in two junior high schools and a senior high school in Jiangxi province were selected with stratified cluster sampling and investigated with Subjective Well-Being Scale for Adolescents and Family Assessment Device.Results The left-behind students with single parent/parents working out had lower scores(4.83±0.88/4.84±0.87,3.97±0.99/3.99±1.02,4.30±0.68/4.32±0.68) than common students(4.93±0.88,4.12±1.01,4.39±0.69) in friendship satisfaction,environment satisfaction,and life satisfaction(P < 0.05).The students with their parents working out had a higher score of negative affection(2.67±0.89) than students with their parents at home(2.55±0.91) or with mother or father working out(2.54±0.84).The left-behind students with single parent/parents working out had higher scores(2.31±0.32/2.31±0.30,2.21±0.47/2.25±0.44) than common students(2.27±0.31,2.20±0.42) in roles and affective involvement(P < 0.05).Except negative affection,other dimensions were significantly related to problem solving for students with single parent working out(P < 0.05).For different students,seven dimensions of family functioning had different degrees of relationship to their life satisfaction,positive affection,negative affection,and overall subjective well-being.For different students,different variables were included in the overall subjective well-being model,and the total subjective well-being score was reduced with the increases of scores of independent variables.Family functioning could predict the level of subjective welleing.Conclusion Single parent or both parents working out could affect some dimensions of subjective wellbeing among left-behind students and family functioning has a great influence on subjective well-being of the students.