Acyi-coenzyme A oxidase 1 (ACOX1) is the first and rate-limiting enzyme in peroxisomal fatty acid β-oxidation and plays a key role in fatty acid metabolism and fat deposition.It is an important candidate gene for meat quality selection through marker-assisted selection (MAS).Genomic structural analysis showed that bovine ACOX1 shares 86% identity with human ACOX1.Using PCR-SSCP technology, we discovered one single nucleotide polymorphism (SNP) (A1865C in exon 13)of the ACOX1 gene.Allele frequencies of the SNP were investigated and evaluated by the X2 test in641 cattle populations; only the Jiaxian red population was not in Hardy-Weinberg equilibrium.Gene heterozygosity, effective allele numbers and polymorphism information content of the bovine ACOX1locus in seven populations varied from 0.2778 to 0.4954, 1.3846 to 1.9817 and 0.2392 to 0.3727,respectively.We also looked for a potential association of this SNP with ultrasound traits in 327individuals and found a significant effect on ultrasound baekfat thickness and ultrasound marbling score in the populations tested (P<0.05)..Meat quality traits were analyzed in another 61 Qinchuan individuals to determine associations with genotype.Animals with the genotype AA had higher mean values of backfat thickness than those with genotypes AC and CC.We conclude that this SNP of the ACOX1 gene has potential as a genetic marker for meat quality traits in cattle reproduction and breeding.