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Bovine mastitis is a very complex and common disease of dairy cattle and a major source of economic losses to the dairy industry worldwide.In this study, the bovine TLR4 was taken as a candidate gene for mastitis resistance.This study aimed to analyze the associations of single nucleotide polymorphisms (SNP) or haplotype and somatic cell score (SCS) in 404 Chinese commercial dairy cattle including Chinese Holstein, Sanhe cattle and Chinese Simmental breeds.The PCR (polymerase chain reaction) and sequencing methods were used for detecting genotype and allele frequency distribution of two SNPs (rs29017188, rs8193046), statistical results showed that T allele at rs8193062 and C allele at rs8193064 were predominate alleles.Moreover, six SNPs, including two SNPs (rs29017188, rs8193046) and four SNPs (rs8193060, rs8193069, rs8193062 and rs8193064) which were chosen according the polymorphism level for the same cattle populations in previous studies, were used for haplotype analysis, the results revealed that twenty-one haplotypes were found in the mentioned animals, of which, Hap1 (30.5%) and Hap2 (30.4%) were the common haplotypes.Hap2, Hap4 and Hapl2 might negatively effect on milk SCS, whereas Hap13 might positively effect on milk SCS.The results in this study might assist in marker assisted selection (MAS) and provided some reference to be implemented in breeding programs to improve the mastitis resistance of dairy cattle.