Diptychus maculatus is a national second-class wild protected animal. Although artificial breeding and stock enhancement have been achieved, bottleneck problems such as genetic homogeneity still exist. Therefore, it is of great significance to conduct research on the relationships between the morphological traits and body weight of D. maculatus for the stable inheritance of excellent traits. In this study, 102 female and 104 male fish from the Muzart River were taken as the research objects. The body weight, 12 traditional morphological traits [total length (X₁), body length (X₂), body width (X₃), body depth (X₄), head length (X₅), snout length (X₆), eye diameter (X₇), interorbital distance (X₈), caudal peduncle length (X₉), caudal peduncle height (X₁₀), mouth cleft width (X₁₁), and mouth cleft height (X₁₂)], and 21 truss morphological traits [the distance from the tip of snout to the end of the end of the back of the head (X₁₄), the origin of the dorsal fin (X₂₃), the origin of the pectoral fin (X₂₂), the origin of the pelvic fin (X₂₄), the distance from the end of the head dorsum to the origin of the dorsal fin (X₁₅), the origin of the pectoral fin (X₂₅), the origin of the pelvic fin (X₂₆), the distance from the origin of the dorsal fin to the end of the dorsal fin base (X₁₆), the origin of the pectoral fin (X₂₇), the origin of the pelvic fin (X28), the origin of the anal fin (X₂₉), the origin of the ventral caudal fin (X₃₀), the distance from the end of the dorsal fin base to the origin of the dorsal caudal fin (X17), the origin of the pelvic fin (X₃₁), the origin of the anal fin (X32), the origin of the ventral caudal fin (X33), the distance from the origin of the dorsal caudal fin to the origin of the ventral caudal fin (X18), the origin of the anal fin (X₃₄), the distance from the origin of the ventral caudal fin to the origin of the anal fin (X₁₉), the distance from the origin of the anal fin to the origin of the pelvic fin (X₂₀), and the distance from the origin of the pelvic fin to the origin of the pectoral fin (X₂₁)] were measured. The effects of morphological traits on body weight were studied through correlation analysis, regression analysis, and path analysis. The results showed that: (1) The morphological traits that show a significant positive correlation (P＜0.05) with body weight as well as their numbers are different in Diptychus maculatus of different genders and ages; (2) Linear regression equations between morphological traits and body weight were established for male and female populations of Diptychus maculatus. The total determination coefficients (R₂ ) of these equations ranged from 0.946 to 0.993 for the female group and from 0.797 to 0.991 for the male group; (3) Path analysis showed that X₄, X₂, X₂₉, and X₂₄ have the greatest direct effects on the body weight of female fish aged 1+ to 4+ , with path coefficients of 0.615, 0.444, 0.550, and 0.603, respectively. Meanwhile, X ₂₇, X ₂, X ₂₉, and X1 have the greatest direct effects on the body weight of male fish aged 1⁺ to 4⁺ , with path coefficients of 0.439, 0.545, 0.439, and 0.640, respectively. This study enriches the relevant morphological data of D. maculatus and provides a basic theoretical basis for later breeding work.