Primers were designed according to glutathione S-transferase-rho gene from EST database of grass carp.The PCR products were sequenced for detecting polymorphisms in cultured population and two SNPs sites were found:C+129T in exon 1 and C+192T in exon 2.Both SNPs are synonymous mutation.The polymorphisms were genotyped by PCR-RFLP methods.The percentage of CC,TC and TT genotype in C+129T site was 0.69%,18.75% and 80.56%,respectively.The percentage of CC,TC,and TT genotype in C+192T site was 25.4%,48.6% and 26.1%,respectively.A general linear model was used to analyze relationship between GSTR gene polymorphisms and 6 major growth traits.The results indicated that the average value of growth character TT genotype was higher than that of TC genotype in C+129T site,although no significant difference was observed.The average body weight of TT genotype was higher than that of TC and CC genotype in C+192T site (P<0.05).Six diplotypes were constructed based on two SNPs in the experiment population and the average body weight of diplotype D1 was higher than that of D3 diplotypes and D6 diplotypes（P＜0.05).GSTR gene could be recommended as a candidate gene for characterizing grass carp growth traits which could be useful for molecular breeding.