Abstract: Three SNPs loci in IGF-Ⅰ gene in 180 Wenling Grass-chicken including 3 lines were detected by PCR-RFLP method,and its genetic effects on carcass traits were also analyzed. The mutations of T→C,C→A and C→T were identified by PstⅠ,HinfⅠand TaqⅠ， respectively. Three genotypes were acquired in each locus,and line A was at the Hardy-Weinberg equilibrium (Ρ＞0.05) in each locus. The analysis of variance showed that the genotypes of each locus had significant or suggestive difference (Ρ≤0.01 or 0.01＜Ρ≤0.05) in partial carcass traits. The multiple comparisons indicated the Least Squares Means of 3 genotypes in each locus had the property of mutant genotype＞heterozygous genotype＞wild genotype in 6 carcass traits,and the com-genotypes QF∕QF and QE∕QF were suggestive higher (0.01＜Ρ≤0.05) than PE∕QE in 4 carcass traits. And the mutant allele of each locus had additive effect on partial carcass traits. The genetic distance between line A and B was 0.005 3,indicating they were in the same branch through cluster analysis.