Abstract: The activation and insemination methuds of cryopreserved sperm from three species of Chinese carps (Ctenopharyngodon idella, Hypophthalmichthys molitrix and Megalobrama amblycephala) have been studied. The effect of the osmo-lality of activating solution an fertility of cryopreserved sperm was examined.When sperm-ova insemination ratio was 1:4(V/V)，there was no significant di-fference in fertility of frozen sperm between in fresh water and. in 171-342mOsm/l solution. When sperm--ova ratio was 1:16,fertility of frozen sperm in NaCl solution with osmnlality of 171-342mOsm/l was significantly higher than that in fresh water. Ova could be fertilized for 6 min in above medium.but 2 min in fresh water.Basic extender (pH>8.7) was unsuitable for sperm storage,and the slightly acidic activating solution (pH6.3) rues unfavourable for the activation and insemination of cryopreserved sperm. The thawing sperm stored at 4℃ for 1.5 hour and did not significantly influence motility and fertility. A significant positive correlation (r=0.97) between the activity of cryopreserved sperm and fertility was shown. The regression equation was Y=3 .68 ± 1.23x.