Triplophysa yarkandensi is an indigenous fish in the Tarim River in Xinjiang Province. To accumulate theoretical breeding data for T. yarkandensi, the effects of morphological traits on body weight were explored. Body weight (Y) and nine morphological traits were measured, including the total length (X₁), body length (X₂), body height (X₃), head length (X₄), tail stalk length (X₅), snout length (X₆), eye length (X₇), interorbital space (X₈), and slit width (X₉). Correlation analysis, path analysis, and regression analysis were used to determine the three main morphological traits that affect body weight (Y). The best-fitting model for the three main morphological characters and body weight was determined by curve fitting. Overall, there was a significant positive correlation between body weight and morphological traits (P＜0.01); the length of the tail stalk, eye diameter, and eye distance were not related to each other (P＞0.05). There were multiple collinear relationships between other traits and body weight; head length had the most direct effect on body weight (0.470), and body length had the most indirect effect on body weight (0.447), although head length and body length were the main variables that affected body weight. Head length was the largest direct determinant of body weight (0.221), and the largest co-determination coefficient of body length and head length was 0.341. The sum of the determinants of body weight (Y) for the three morphological traits was 0.958, which explained 95.8% of the variation. The linear equation for the three main morphological traits and body weight was Y=–2.8+2.94X₂+0.764X₄+0.906X₅ (R² =0.958). The optimal model equations for the three main morphological traits and body weight contained exponential functions, a power function, and a linear function, and the model equations were Y=2.739e^0.158X2 (R² =0.936), Y=4.946X₄ ^1.100 (R₂ =0.931), and Y=9.582+8.876lnX₅ (R² =0.807) for the curve equation for the tail stalk length and body weight (Y). This indicated that the tail stalk length was not a main morphological factor and was the only variable that could not explain the change in body weight. Body length and head length were the main selection traits, and tail stalk length was an auxiliary trait, which could be used to guide T. yarkandensi breeding.