Abstract: In this paper,the measured body weight traits(body weight,fresh and dry weight of soft tissue,fresh and dry weight of the shell),body size traits(shell length,shell height and shell width) and condition index of 1a~2a bivalve of Cultellum scalprum from Funing Bay in Fujian Province were described.The correlation between the traits,growth types of the traits,and the effect of body size traits on body weight traits of the bivalve were analyzed with correlation,regression and path analysis,respectively.The results showed that variable coefficient(CV) of weight traits was 28.09%~43.10%,CV of body size traits was ≤ 15%,CV of weight traits was larger than that of body size traits of bivalves.There were significant correlation coefficients between body size and weight traits of the bivalve(P < 0.01),and the regression relationship between the traits could be expressed by power function equation.Compared with body size traits(shell length,shell height and shell width),the body weight of the bivalve showed positive abnormal growth(b>1.0,P < 0.01);shell width and shell length showed isokinetic growth(b=1.0,P < 0.01);shell height and shell length,as well as shell width and shell height showed negative allometric growth respectively(b < 1.0,P < 0.01).The multiple regression equation was obtained to estimate body weight of the bivalve:Y=-2.535 1+0.046 0X₁+0.060 4X₂+0.295 8X₃(shell length:X₁,shell height:X₂ and shell width:X₃).Based on path analysis,the direct effects of shell width on weight traits(body weight,the fresh weight and dry weight of the soft tissue) were the largest;and the direct effects of shell length on body weight,shell height on fresh and the dry weight of the soft tissue were the second;the indirect effects of shell height through the shell width on body weight,fresh weight and the dry weight of the soft tissue were the largest,respectively.