Black Muntjac(Muntiacus crinifrons) is a critically endangered mammalian species.For the first time,this study investigated the testis and spermatozoa morphology of M.crinifrons by using Gimsa staining.The parameters of acrosome abnormality were recorded and compared with those of Huanghuai Goat.The results showed that the long axis of Black Muntjac testicle was 4.25 cm while the short axis was 2.05 cm,obviously lower than the values of Huanghuai Goat testicle.The length of Black Muntjac spermatozoon was 54.80 μm and its acrosome was in a cylinder shape.The acrosome covered approximately 2/3 sperm head,while Huanghuai Goat acrosome covered only 1/2 sperm head.Furthermore,we found that the percentage of teratosperm in epididymal caudae was 21.50%±4.23%,and the spermatozoa mobility was 0.20.The percentage of sperm with protoplasmic droplet and abnormal acrosome was 30.17%±4.45% and 30.50%±3.99%,respectively.These data will be useful for assisted reproduction and protection of this endangered species.