Abstract: In order to investigate the effect of tibia circumference on the occurrence of leg disease in Muscovy ducks, Wen’s white feather Muscovy ducks N101 was the research object in the experiment, and the incidence rate of leg disease and weight gain rate of male ducks were investigated through counting the incidence of leg disease and body weight change of the 6 th generation of Muscovy ducks.Tibia circumference at 30 weeks of age was measured in the 10 th generation ducks of N101 strain, large tibia circumference, small tibia circumference and common tibia circumference families were established, and the occurrence of leg disease at the age of 10 weeks of ducklings and large and small tibia circumference of ducklings were calculated.The results showed that the incidence of leg disease and body weight of male ducks in the 6 th generation of N101 strain increased with the increase of week age, and the incidence rate was similar to the increase rate of body weight.The tibia circumference of parent male ducks in the large tibia circumference family was extremely significantly higher than that in the common family and the small tibia circumference family（P＜0.01）;the tibia circumference of parent male ducks in common family were extremely significantly higher than those in small tibia circumference family（P＜0.01）;the tibia circumference of parent female ducks in large tibia circumference was significantly higher than in the common family（P＜0.05）, and was extremely significantly higher than those of small tibia circumference family（P＜0.01）;the tibia circumference of parent female ducks in common family were significantly higher than those in small tibia circumference family（P＜0.05）.The incidence of leg disease was lower in the offspring of large tibia circumference family（0.7% and 0.8%, respectively）.The incidence of leg disease was higer in the offspring of small tibia circumference family（ 3.6% and 4.5%,respectively）.The incidence of leg disease was 1.3% and 0.9% in the offspring in the common family, which was between small tibial circumference and large tibial circumference.The tibia circumference of the offspring male ducks of large tibia circumference family was extremely significantly higher than that of the male ducks with small tibia circumference（P＜0.01）.These results indicate that the shank circumference of Muscovy ducks has a strong genetic character, and the occurrence of leg disease of male ducks is related to body weight growth rate and tibia circumference.