The linkage relationship between milk protein loci and lactation trait loci, such as milk yield, fat percent, protein percent and dry matter percent, were fully investigated by the methods of heterozygosity analysis and linkage group analysis. The results showed that each single protein locus showed a higher homozygosity while the three easein loci showed a lower homozygosity when they were investigated simultaneously. There was no significant regression of deviations in lactation traits on overall marker heterozygosity. Significant linkage between kappa-CN locus and milk fat percent and protein percent, and that between alpha sl-CN locus and 305-d milk yield were found.