The polymorphism of hemoglobin (Hb), serum albumin (Alb), trandferring (Tf) and adenosin deaminase (Ada) in the blood of Emberiza elegans, Phylloscopus inornatus, E. aureola, Lanius tigrinus, Passer montanus, and E. spodocephala in Zhalong National Nature Reserve were studied by SDS-polyacrylamide-gel electrophoresis. All the protein loci of the six Passeriformes species exhibited polymorphism, and Ada locus had a relatively high heterozygosity. The analysis of average heterozygosity demonstrated that P. inornatus had a higher population genetic variance, while E. spodocephala was relatively stable. The six species could be classified into two clusters. E. elegans, E. aureola, E. spodocephala and P. inornatus were clustered into one group, while P. montanus and L. tigrinus were clustered into another group. This clustering was consistent with the actual taxonomic status of the six species. The higher thermoregulation index and predation pressure of the study area did not lead to the substantial variation of hereditary constitution of the six species, possibly due to the gene intercommunion between the six species and the outside of the study area, which decreased the variance and differentiation of the population genetics of the six species.