In investigating sexual behavior,sexual attitudes and sexual knowledge among college students,a questionnaire survey was conducted among 1151 college students in Beijing.Results show that(1) Self-constructed or recomposed Questionnaire on sexual behavior,sexual attitudes and sexual knowledge had good reliability and validity;(2)13.7%of the college students had experienced sexual intercourse,and the difference is not significant among grades but significant between sexes.Significant difference in sexual attitudes and sexual knowledge is found among grades and between sexes;(3) Sexual behavior,sexual attitudes and sexual knowledge are positively correlated.Sexual and contraceptive knowledge and sexual attitudes could predict sexual behavior.