Abstract: The sheep semen were freezing by liquid nitrogen vapour method and apparatus freezing frozen method respectively, measuring thawed semen by sperm motility, acrosome integrity, membrane integrity and aspartate aminotransferase and lactate dehydrogenase activity to compare effect of different methods of freezing semen quality after thawing；measuring enzyme activity after semen dilution, equilibration, apparatus freezing frozen method to compare the release amount of aspartate aminotransferase and lactate dehydrogenase at different stages. The results showed that the sperm motility and membrane integrity after apparatus freezing frozen method were highly significant higher than the liquid nitrogen fumigation freezing method (P<0.01)；aspartate aminotransferase and lactate dehydrogenase activity after apparatus freezing frozen method were highly significant lower than that of liquid nitrogen fumigation method (P<0.01). Aspartate aminotransferase and lactate dehydrogenase activity of semen diluted were highly significant lower than the activity of frozen semen (P<0.01). The results showed that the sheep semen quality by apparatus freezing frozen method was better than the liquid nitrogen fumigation freezing method. For sperm, the release of aspartate aminotransferase was in the equilibrium phase, and the release of lactate dehydrogenase was in the freezer stage.