Objective To explore the motivation and their psychological pressure of premarital sex in female college students.Methods 32 female college students who had premarital sex received from March 2013 to April2015in a university hospital of Chengdu had in-depth interviews and 504 female students from the university（including 50 who had premarital sex）were chosen to take questionnaires.Their motivation and psychological pressure of premarital sex under the two survey methods were compared.Results There were six types of motivation of premarital sex in female college students

namely " curiosity"

" pending marriage status"

"speech cajole"

"access to economic benefits"

"actively pleasing" and "sexual violence"

and the differences of types of motivation of premarital sex under the two survey methods were not statistically significant;there were statistically significant differences of different types of motivation of female premarital sex in negative sexual experiences

fears of negative social evaluation

worries of physiological injury and fears of damaging marital relations（F=78.700

F=25.196

F=11.508

F=14.524

P<0.01）.Conclusion Universities and colleges should develop targeted interventions according to the motivation of premarital sex in female college students in order to promote their sound development in body and mind.