Abstract:Thirteen plasma proteins(enzymes) polymorphism were examined in 28 samples of "Songliao black" pig by means of PAGE in this study.The results showed that Alb, Pa2 and Cp were monomorphic, while Pa1, Po1, Po2, Tf, Ptf, Akp, Hpx, Am1, Am2, Es were polymorphic.These loci had alleles from two to four respectively.The results of Chisquare test showed that Pa1, Pa2, Ptf, Akp were not in Hardy-weinberg balance while Po1, Po2, Tf, Am1, Am2, Hpx, Es were in Hardy-weinberg balance.The mean number of effective alleles, mean heterozygosity and homogeneity index were 2.0779, 0.5083 and 0.1288 respectively.