Abstract: Objective To study the effects of Percoll gradient centrifugation and swimming up technique on the sperm viability, the hypoosmotic swelling rate of human spermatozoa tail and the percentage of morphologically normal spermatozoa. Methods Semen samples were collected from 12 male infertility patients. Sperm selection was performed respectively using Percoll gradient centrifugation and swimming up technique. Sperm viabilities and the hypoosmotic swelling rates of human spermatozoa tail before and after sperm selection were analyzed by Eosin stain. Sperm morphological changes before and after sperm selection were evaluated by Modified Papanicolaou stain. Results ①The sperm viability and the hypoosmotic swelling rate of human spermatozoa tail were significantly increased after Percoll gradient centrifugation and swimming up （P<0.01）. No significant difference was found in comparison of sperm viability and the hypoosmotic swelling rate of human spermatozoa tail between the two selection methods（P>0.05）. The rate of sperm with type B-G tail swelling was significantly improved after Percoll and swimming up（P<0.01）, However, there was no significant difference of type B-G tail swelling rate between the two selection methods. ②The rate of morphologically normal sperm significantly was increased after Percoll and swimming up, Meanwhile,the rate of normal morphological sperm after swimming up was higher than that after percoll（P<0.05）. The rate of Tapered sperm, Irregularity sperm and Neck/Midpiece defect sperm after swimming up were significantly decreased（P<0.05）. The rate of Tapered sperm,Irregularity sperm, and Tail defect sperm after Percoll were significantly decreased. However, the rate of Irregularity sperm, Neck/Midpiece defect sperm and tail defect sperm after swimming up were significantly lower than those after Percoll (P<0.05).Conclusion After sperm selection using Percoll gradient centrifugation and swimming up technique, the sperm viability, hypoosmotic swelling rate of human spermatozoa tail and rate of morphologically normal spermatozoa are obviously improved. These two sperm selection methods may be widely applied in reproductive medicine. Swimming up technique is better than Percoll gradient centrifugation.