Abstract: This study aimed to assess the impact of coenzyme Q10 addition in freezing extender on cryopreservation efficacy of cashmere goat semen.The fresh semen samples were collected and were cryopreserved with the freezing extender supplemented with 4μg/mL,40μg/mL or 400μg/mL of coenzyme Q10,respectively.After thawing,the sperm motility rate,membrane integrity,acrosome integrity,DNA integrity,mitochondrial membrane potential and reactive oxygen species(ROS)level of the cryopreserved semen samples treated with different concentrations of coenzyme Q10 were evaluated by flow cytometry assay and computer-assisted sperm analysis system(CASAS)and were statistically assessed.The results showed that after the freezing-thawing process,the sperm motility rate,membrane integrity and acrosome integrity were increased significantly when 40μg/mL of coenzyme Q10 was supplemented in the freezing extender(P<0.05).In addition,the sperm of the semen samples cryopreserved in the freezing extender supplemented with 40μg/mL or 400μg/mL of coenzyme Q10 showed significantly higher mitochondrial membrane potential and significantly lower ROS level(P<0.05).In conclusion,supplementation of 40μg/mL of coenzyme Q10 in the freezing extender can significantly improve the antioxidant activity and cryopreservation efficacy of cashmere goat sperm.