Effects of 9 morphometric traits on body weight of three aquaculture populations of mandarin fish (Siniperca chuatsi) were analyzed by using correlation analysis,multiple regression and path analysis.Data of body weight,total length,standard length,body depth,head length,eye diameter,trail length,caudal peduncle length,caudal peduncle depth were collected in this study.Results of correlation analysis showed that there were significantly correlations between most morphometric traits and body weight (P<0.01).According to the regression coefficient test,there was significant difference among different populations and multiple regression equation were set up to estimate body weight.Path analysis indicated that total length and body depth bared strong direct effect on body weight,and the path coefficients (Pi) and determination coefficient (di) decreased with the month age increasing.The comprehensive coefficient of determination of total length and body depth maintained stable,which indicated that body weight was mainly affected by total length and body depth at early age.This paper provides theoretical evidence and perfect measure target for breeding of Siniperca chuatsi in aquaculture.