Abstract: Three SNP sites of IGF-Ⅱgene in Jinghai Yellow chicken was detected by PCR-SSCP method, its genetic effects on production performance were also analyzed. And the results showed that the mutations of C→G，G→C，G→A in P1，P2，P3 sites were identified, respectively. There were three genotypes in each site, and three genotypes in P1 site deviated the Hardy-Weinberg equilibrium(P＜0.05). The Least Square Means analysis showed the difference of the egg number in 300 days between AA and BB genotypes were significant(P＜0.05), and A was an enhancing allele, B was a leaky one; CD has higher 12-week-weight than CC(P＜0.05); EE and EF have higher average-egg-weight than FF(P＜0.05), and E was an enhancing allele, F was a leaky one. The com-genotypes AA/CC/EF has higher average-egg-weight than AB/CD/EE and AB/CD/EF(P＜0.05); AB/CD/EF has higher 300-day-weight than AA/CC/EF and BB/DD/EE(P＜0.05).