In order to determine the influence of external morphological traits of wild Pinctada maxima in Nansha population on its body weight and provide the best reference index for artificial breeding, the 1-year-old wild P. maxima collected in the natural sea area of Nansha Islands were taken as the research objects. The shell length, shell height, shell width and hinge length of external morphological traits and the body weight were measured and counted, and the correlation, multiple stepwise regression and path analysis were carried out. The results showed that the coefficient of variation of each trait index was [13.751% , 38.947%], and the correlation coefficients of each trait reached a very significant level (P<0.01). The optimal regression equation was established by excluding morphological traits with no significant difference, R_² = 0.933; The path analysis results showed that the external morphological traits with the greatest direct effect on body weight of P. maxima in Nansha population were shell width (0.439), and the indirect effect of shell length on body weight through shell height was the greatest (0.384). The determination coefficient of shell width on body weight was 0.193, and that of shell width through shell height was the greatest (0.312). The results show that the selection of shell width should be paid attention to when the body weight of wild P. maxima in Nansha population is used as the breeding target.