Abstract: Objecfive The present study was made to learn college students’sexual knowledge and behaviors to provide facts for the development of health education about sexually transmitted discases and AIDS and for the implementation of behavioral intervention among the population．Methods Questionnaire was done among college students from grade one to grade four in two universities．Results A total of 2 2 940 students from two universities were involved in the invesfigation．It was shown that 94.6％ of the students had had sexual knowledge at jtinier middle school and high school and 46.3％ of them acquired sexual knowledge through pornographic media；witll 15.8％，3.1％ and 2.0％ of them obtaining the knowledge from their schools．Teachers and parents respectively．Students who were aware of the three routes of AlDS transmission accounted for 91.6％ and 68.8％ of them assumed that AIDS could be transmitted by mosquito bites，public toilets and closestools，too．52.1％ of the students knew that condom use was able to prevent AlDS．And 13.1％ of the students had had sexual intercourse．With the mean age at which the first sex behavior occurred being 19．5 yeas．The rote of condom I．1 e in the first and last sexual behaviors was 29.2％ and 47.8％ respectively．There were 1.4％ of the students were once diagnosed as having STD Conclusion College students’knowledge about the prevention and control of STD and AlDS was inadeqaate in terms of the depth and extensiveness．With a low rate of knowledge about condom use preventing AIDS and its use．So schools should be taken as major sites where the prevention of STD and AIDS is conducted in the future．