Abstract: This study aimed to find the genetic markers that control the milk-producing traits of Hu sheep for breeding purpose.Molecular genetic polymorphism of the prolactin gene in the sheep populations was studied.More than 41 parturition ewes were used by separating the ewes from the lambs 20 hours on the 4th day after giving birth,and manually lactated to collect milk from them.On the following day,the milk collection took place at 7am,1∶30pm,and 7pm every day for 8weeks.Each milk sample was analyzed for its chemical composition.After the entire gene sequence was obtained for organizing and analyzing by SPSS 13.0to locate and identify the SNP loci by MEGA6,followed by the linkage and haplotype analysis.Finally,using the least squares method,the correlation between the polymorphisms and the milk-producing traits was established.The results showed that the average milk content of Hu sheep during 56 days was(0.52±0.07)kg·d^-1,and the fat,protein,sugar,and total solids contents in the milk were(3.83±0.90)%,(5.52±0.63)%,(5.50±0.73)%,and(15.13±1.61)%,respectively.Based on the genetic and the linkage disequilibrium analyses,4 milk-producing traits were found to significantly correlate with the SNP sites in Hu sheep.At the PRL4244 site,the milk producing amount of the GG type in the 8th week of lactation was significantly higher than the TT genotype(P<0.05);at the PR1039 site,the fat content in the milk during mid-term of the AC-type was significantly higher than AA and CC types;at the PRL1228 site,the fat content of the AC-type was significantly higher than AA and CC types in the early stage(P<0.05),while that of the AC type during mid-term was significantly higher than AA and CC types(P<0.01);the total solids of AC in mid-term were significantly higher than those of the CC genotype(P<0.05),and the total solids of AC type in the mid-term was significantly higher than the CC type(P<0.05);at PR2351 sites,the fat contents of the AG type in the early stage and mid-term were significantly higher than AA and GG genotype(P<0.05),while the protein ratio of the AA type in mid-term was significantly higher than the AG and the GG genotype(P<0.01),and the total solids of the AG type in mid-term were significantly higher than those of the AA or the GG genotype(P <0.01);and,at PR4591 sites,the milk fat content of the CC type in the early stage was significantly higher than the TT genotype(P<0.01),while the protein ratio of the CC type in mid-term was significantly higher than those of the TT and TC types(P<0.01),and the total solids was significantly higher than the TT type in the early stage.There were a total of 25 haplotypes detected,the frequency of 7haplotypes were more than 0.02,and the protein content of CCATT haplotype was significantly higher than that of AAATT haloytpe.No significant diffience were existed in the milk ingredient and milk content among other haplotypes.