Abstract: In order to study the fat-tail characteristics of Duolang sheep and its correlation with body weight and body size of Duolang sheep, 312 healthy and 3-year-old adult Duolang sheep（244 female sheep and 68 male sheep） with similar body weight were randomly selected to measure their body weight（y）, tail length（x₁）, tail width（x₂）, tail height（x₃）, body height（x₅）, body length（x₆）, chest circumference（x₇）, chest depth（x₈）, chest width（x₉）, circumference of cannon bone(x₁₀)and height at hip cross(x₁₁),and tail volume（x₄）was calculated. The tail volume difference between male and female sheep was analyzed, and the tail type of male and female sheep was analyzed according to the tail volume. The correlation between tail traits, body weight and body size was analyzed, and the optimal regression equation of body weight were constructed. The results showed that the tail volume of male Duolang sheep was higher than that of female sheep（P＜0.05）.According to the tail volume, male and female sheep could be divided into small tail type, middle tail type and big tail type. The tail length, tail width, tail height, tail volume, body height, body length, chest circumference, chest depth, chest width of male and female sheep were significantly positive correlated with body weight（P＜0.01）. The optimal regression equation of body weight constructed as follows: y（male）=1.313x₇+0.001x₄-0.209x₂-58.347, and y（female）=0.789x₇+0.737x₁-0.083x₂+0.270x₈-35.748. The above results indicated that tail traits of Duolang sheep were closely related to body weight, which revealed that tail characteristics had certain influence on meat production performance. In the production performance measurement and breed selection of Duolang sheep, attention should be paid to gender differences and tail characteristics.