Abstract: Genetic polymorphisms of microsatellite locus BMS2508, which was closely linked to the ovine fecundity gene FecB, were detected in prolific (Small Tail Han sheep) and non-prolific breeds of sheep (Texel, Dorset and Chinese Merino). The linkage disequilibrium between microsatellite locus BMS2508 and FecB gene of Small Tail Han sheep was also ana-lyzed. There was the same mutation (A746G) of BMPR-IB gene in Small Tail Han sheep as that of FecB in Booroola Me-rino ewes, but the FecB mutation was absent in Texel, Dorset and Chinese Merino sheep. The genotype frequencies of BB, B+ and ++ were 0.485, 0.398 and 0.117 in Small Tail Han sheep, respectively. There were eight alleles varied from 94 bp to 116 bp and 15 genotypes detected at BMS2508 locus in four sheep breeds totally 438 individual. The preponderant allele was 100 bp, 94 bp, 94 bp, 112 bp, 100 bp, 100 bp, 112 bp, and the frequency was 0.453, 0.544, 0.802, 0.475, 0.483, 0.439, 0.389 in Small Tail Han (n=307), Texel (n=45), Dorset (n=46), Chinese Merino (n=40), and BB group (n=149), B+ group (n=122), ++ group (n=36) from Small Tail Han, respectively. In Small Tail Han sheep, linkage analysis indicated that there was certain linkage disequilibrium between 100 bp allele of microsatellite BMS2508 and B allele of FecB gene (D′ =0.408), and certain linkage disequilibrium between 110 bp and 114 bp alleles of microsatellite BMS2508 and + allele of FecB gene (D′=0.513).