Abstract: To investigate the relationship between eye muscle area and backfat thickness with body weight and body size of Grassland short-tailed sheep, the eye muscle area（Y₁）, backfat thickness（Y₂）, body weight（X₁） and body size traits（body length X₂,body height X₃,chest depth X₄,chest circumference X₅, chest breadth X₆,cannon bone circumference X₇, hip width X₈） of 1 115 adult Grassland short-tailed sheep（103 males, 1 012 females） were measured by ultrasonic detection technology. The correlation analysis of the above indexes was carried out, and the stepwise regression analysis was carried out with body weight and body size as independent variables and eye muscle area and backfat thickness as dependent variables. A stepwise regression equation was established to analyze the direct and indirect effects of body weight and body size on eye muscle area and backfat thickness with the passage analysis. The results showed that body weight and body size traits of female Grassland short-tailed sheep were extremely significantly positively correlated with eye muscle area and backfat thickness（P＜0.01）; the body weight of rams was extremely significantly positively correlated with eye muscle area and backfat thickness（P＜0.01）; body length, chest circumference, and circumference of cannon bone were extremely significantly positively correlated with eye muscle area（P＜0.01）; body length and chest circumference were extremely significantly positively correlated with backfat thickness（P＜0.01）, and circumference of cannon bone and hip width were significantly positively correlated with backfat thickness（P＜0.05）. The result of path analysis showed that body weight had the greatest effect on the eye muscle area and backfat thickness, followed by hip width. For the male and female Grassland short-tailed sheep, the optimal linear regression equations of eye muscle area with body weight and body size traits were Y₁=2 324.163+29.512X₁-42.449X₄-43.696X₈ and Y₁=-301.896+9.420X₁+32.620X₇ +22.435X₈-18.810X₆+3.417X₅, respectively. The optimal linear regression equations for male and female sheep of backfat thickness and body weight and body size traits were Y₂=-1.517+0.111X₁ and Y₂=-4.636+0.035X₁+0.134X₈+0.038X₂ +0.034X₅-0.046X₄, respectively. The results indicated that body weight and body size traits such as hip width, chest circumference and tube circumference had a good predictive effect on the eye muscle area and back fat thickness indicators of Grassland short-tailed sheep.