The GHRH-GH-ⅠGFs growth axis plays an essential and central role in body growth. The insulinlike growth factor, located downstream of the axis, is a critical conduction factor of GH transmission and biological function exertion. In this experiment, we specifically isolated 5 exons and 3 introns (intron1, intron3, and intron4) of IGFⅠa gene in Cyprinus carpio var. jian. A total of 8 SNPs were screened by comparing the sequences of 10 individuals. PCRRFLP was applied in detecting the intron 1_C175G genotypes of 372 individuals from 5 families; the intron 1_A993G and intron 4_A511C genotypes of 987 individuals from 12 families. And then we identified the genotype, counted the allele frequency and analyzed the correlation between the three SNPs and weight gain. The results showed that the GG genotype frequency (male 0.43 and female 0.44) was the highest in intron 1_C175G, while this locus showed no association with weight gain. Intron 1_A993G locus significantly correlated with male weight gain in adult stages (P<0.05) and AG genotype displayed the highest frequency, 0.76 in female and 0.72 in male. 0.48 in female and 0.47 in male of CC genotype was the highest allele frequency for locus intron 4_A511C, which was remarkably associated with both male and female weight gain in both juvenile and adult stages(P<0.01). This experiment indicated that the expression of IGFⅠ gene varied between the different growth stages in Cyprinus carpio var. jian. Furthermore, expression diversity also existed between male and female individuals even at the same growth stage. The intron 1_A993G and intron 4_A511C were found significantly related with weight gain and could be considered as references in molecular breeding in Cyprinus carpio var. jian.