In order to find out the main growth traits of Portunus trituberculatus which have influence on body weight, and define degree of correlation among characters， thirty eight fullsib groups and fifteen halfsib groups of Portunus trituberculatus were obtained by directional mating techniques. Full carapace width(X¹),carapace width(X²),carapace length(X³),body height(X⁴),and body weight (Y) of each family on 80 d,100 d and 120 d were measured. The phenotype correlation coefficients and the genetic correlation coefficients were calculated by correlation analysis at the different ages. The first 4 morphometric attributes (X¹-X⁴) were used as independent variables, and body weight (Y) was used as a dependent variable for path analysis. Path coefficients, and determination coefficients were calculated in path analysis. The results showed that the phenotypic correlation of the five traits was between 0.759 and 0.972,and the genetic correlation was between 0.170 and 0.975. All five correlation coefficients achieved very significant difference（P<0.01）levels. The direct effects by the characters have an order at the three stages,80 d: X¹>X²>X³>X⁴,100 d: X¹> X³> X²> X⁴,120 d: X³> X²> X¹> X⁴, among them X¹ weighted the most to the body weight on 80 d and 100 d, X¹ and X³ weighted the most to the body weight on 120 d. Full carapace width which have the largest direct impact on body weight (0.471 9) is the most important indicators for indirect selection of body weight. Multiple regression equation of X¹,X²,X³,X⁴) to body weight at different developmental stages was obtained as: 80 d Y=-54.113+0.491X¹+0.632 X²+0.325 X³+0.451X⁴; 100 d Y=-123.484+0.627 X¹+0.928X²+1.433X³+0.152 X⁴; 120 d Y=-158.239+0.137 X¹+1.410 X²+2.370X³+0.800X⁴.The high compound correlation index(R²=0.960,0.971,0.892) indicated that these growth traits had direct influence on body weight. Efficient scheme of multiple trait selection will be made if we obtain definite quantitative relationship between each two characters．This study provides theoretical evidence and perfect measure target for breeding of Portunus trituberculatus.