Abstract: Eleven growth traits of 2-year-old Cyprinus carpio var.wananensis,Cyprinus carpio Songhe and Cyprinus carpio Songpu mirror were randomly measured,including the body mass(Y),total length(X₁),body length(X₂),body height(X₃),body width(X₄),tail handle length(X₅),tail handle height(X₆),head length(X₇),length of proboscis(X₈),diameter of eye(X₉),and eye interval(X₁₀).Correlation coefficient analysis,path analysis and multiple regression analysis were used to obtain the correlation coefficient,path coefficient and determination coefficient of morphological traits and body mass,respectively.The multiple regression equation of morphological traits affecting body mass was established,of which ten morphological traits were self-variables and body mass were dependent variables.The results of correlation coefficient analysis showed that some of the morphological traits of the three common carp populations were significantly correlated with body mass(P＜0.05).Path analysis showed that the main morphological traits affecting body mass reached the significant level(P＜0.05).Body length,body height,body width,head length,and eye interval were the main morphological characteristics of C.carpio var.wananensis that affect body mass.Body length,body height,body width,and tail handle height were the main morphological characteristics of C.carpio Songhe that affect body mass.Body length,body height,body width,tail handle height,and eye interval were the main morphological characteristics of C.carpio Songpu mirror that affect body mass.The determination coefficient of body length on body mass in three varieties of common carp was the highest.Using the stepwise regression method,insignificant traits were eliminated,body mass was used as the dependent variable,and the remaining significant traits were used as independent variables to establish the optimal linear regression equation.For C.carpio var.wananensis,the equation was Y=20.788X₂+4.037X₃+9.508X₄+ 3.091 X₇-3.887X₁₀-1 531.973;for C.carpio Songhe,Y=6.61X₂+3.837X₃+10.343X₄+14.076X₆-2 207.838;and for C.carpio Songpu mirror, Y=13.87X₂+6.979X₃+8.254X₄+3.877X₆+12.544X₁₀-2 511.522.This study could provide the important basis for the selection and hybridization of improved varieties and the selection of varieties of C.carpio var.wananensis,C.carpio Songhe and C.carpio Songpu mirror.