Abstract: ObjectiveTo study the effects of obesity on mental health through psychological investigation and analysis for providing physical and mental protection for college students. MethodsA total of 12 900 college students underwent medical examination， personality questionnaires and SCL assessment， excluding those who did not complete the questionnaire due to subjective or objective factors and finally a total of 964 obese students and 11 936 nonobese students were enrolled. ResultsCompared with nonobese students， obese students scored higher in hostility and bigotry significantly. Stratified analysis showed that overweight girls showed the increased score in interpersonal sensitivity and overweight boys showed the increased score in psychotic factor. Stratified analysis also showed that overweight undergraduates had significant change in interpersonal sensitivity， hostility and bigotry; overweight masters had significant change in interpersonal sensitivity and obsession; doctoral students had significant change in interpersonal sensitivity， hostility and anxiety (P<0.05). The number of overweight students with the scores equal or greater than three in interpersonal sensitivity and hostility significantly increased. Stratified analysis showed that the number of overweight boys with the  scores equal or greater than three in obsession was more than that of normal boys，and the number of overweight girls with the scores equal or greater than three in terror was more than that of normal girls. Besides， the number of overweight students belonging to the first category of psychological type was more than that of normal students. ConclusionObesity has effects on mental health for college students as well as study and life， which needs common concern of family， school and society.

Key words: psychophysiology；obesity, students