Abstract: Anti-human semen sera were prepared in rabbits immunized with washed human spermatozoa, seminal plasma, whole semen and seminal plasma specific antigen p30, respectively. The specificity of the anti-sera was identified by the ring precipitation, the double immunodiffusion and the immunoelectrophoresis. The results showed that anti-p30 serum was specific, while other three kinds of anti-sera were not specific for human semen until they were absorbed with the mixture of human colostrum, serum, and saliva.