To study the effects of leucine on the sperm motility of yellow catfish (Pelteobagrus fulvidraco) during early stage of autumn breeding when the quality of sperms and eggs is lower than in summer breeding,males about 100 g were divided into three groups and injected with 200 μL physiological saline (control group),100 μmol/L leucine (moderate leucine treatment group) and 1 000 μmol/L leucine (high concentration leucine treatment group),respectively.It was found that sperm motility of the moderate leucine treatment group declined more slowly detected by the computer assisted sperm analysis (CASA) system.In artificial reproduction,the fertilization rate of the moderate leucine treatment group sperm was 34.91%±4.7%,significantly higher than that of the control group (15.9%±2.2%) (P＜0.05),and the fertilization rate of the high concentration leucine treatment group sperm was 16.4%±3.4%,significantly lower than that of the moderate group (P＜0.05),but not significant different from the control group (P＞0.05).The results showed that moderate leucine could enhance the sperm motility of yellow catfish,but excessive leucine could not improve the sperm reproduction.So appropriate leucine can be added to improve the sperm reproduction of yellow catfish during the early stage of autumn breeding.