To investigate the effect of major morphometric traits of selective group of Trachinotus ovatus at different month ages on body weight,2 635 specimens at 1-month-old stage,4-month-old stage,7-month-old stage,10-month-old stage and 13-month-old stage were measured respectively in terms of total length(x₁),body length(x₂),body height(x₃)and weight(y).Correlation coefficients,path coefficients and determination coefficients of each trait to body weight were calculated through path analysis and multiple linear regression.Effects of each morphometric trait on body weight were also dissected and then the optimal regression equation was established.The results showed that the correlations among 4 traits ranged from 0.017 to 0.960,and all reached significant level(P<0.01)at different stages except that at 4-month-old stage.At 1-month-old stage and 4-month-old stage,the trait with strongest direct effect on body weight was the total length,but that at other stages was the body height.The result of determinant coefficient analysis was consistent with that of path analysis,and the fitness of equations at different stages was good(86.9%-90.6%).It indicated that the major morphometric traits affecting body weight were found and traits for selection should be considered at different stages,which provided technical parameters for selective breeding for T.ovatus.