Growth hormone receptors (GHR) which located on the cell membrane is the only pathway for growth hormone (GH) to get into cells and affect the growth in animals, they play a vital important role on animal growth. Two cDNA sequences and DNA sequences of exon 2-9 of GHR 1, exon 2-8 of GHR 2 were isolated from GIFT strain (Genetically Improved Farmed Tilapia strain, Oreochromis niloticus ) using RT-PCR and PCR in this study. Six and sixteen SNPs were identified on GHR 1 and GHR 2 respectively, only two of which were located at exons. Genotypes were test in eight SNPs ( GHR 1 intron 3_A612G, intron 3_A989T, intron 7_A599C; GHR 2 intron 3_C330T, intron 3_A645G, intron 3_G687T, intron 3_A967G, intron 7_C107T) of 120 individuals from five families of GIFT strain by PCR-RFLP. Correlation analysis between genotypes and weight gain showed that GHR 1 intron 3_A612G and intron 3_A989T associated with male fish weight gain ( P <0.01 and P <0.05) significantly. Similar situation was found in the female population, but the difference was not significant ( P >0.05). Intron 7_A599C was significantly associated with both male ( P <0.01) and female ( P <0.05) fish weight gain. The CC type fish weight gain was significantly higher than AA type’s. On the GHR 2, only intron 3_G687T was found to correlate with female weight gain significantly ( P <0.05). The GT type female fish gain was significantly higher than GG type’s. The correlation between genotypes of 3_A612G, 3_A989T, 7_A599C and 3_G687T and weight gain was detected in 356 individuals from 60 families of GIFT strain (6 individuals in average of each family). There were similar growth situation among different genotypes’ fish, the decreased significance may result in the diverse genetic background and smaller number of samples. Real-time quantitative PCR results indicated that GHR 1 expression in liver of male fish was 1.36 times higher than that in female’s liver, the male fish GHR 2 expression in the tissues (except kidney) was lower than that in the female, which can explain the different effects of GHR 1 and GHR 2 SNP loci on the weight gain of male and female GIFT. In addition, the different influences of GHR1 and GHR2 on the growth result in that only one SNP loci on GHR 2 could affect the weight gain.