Objective: This experiment was designed to evaluate the effects of freezing on human spermatozoal function and structure. Methods: Semen samples were collected from normal fertile 25～35 year old donors

7.5% pure glycerol was used as cryopreservative agent(CPA)

and every sample was frozen at slow cooling rate and fast cooling rate. Results: After freezing－thawing

the whole spermatozoa in the semen without CPA was seen dead；in the semen with CPA

the mean percentage of motility of spermatozoa、spermatozoa tail swelling 、spermatozoa with relatively intact head ultrastructure and zona－free hamster ova penetrated by spermatozoa frozen was significantly lower than that of fresh spermatozoa

and the percentage of every criterion described previously of frozen－thawed spermatozoa cooled at fast rate was significantly lower than that in frozen－thawed spermatozoa cooled at slow rate. Conclusion: Spermatozoal structure and function were damaged to various degrees by freezing－storing－thawing treatment. 7.5% pure glycerol can cryopreserve human spermatozoa

various cooling rates will cause various freezing injury to human spermatozoa

the slow cooling rate is superior to the fast cooling rate and can keep human spermatozoal structure and function fairly well for a relatively long term.