Abstract: The genome DNA was extracted from the blood of six horse breeds including SH, BH, XN, WZ, TB, AI. Four pair of primers were designed based on the sequence of human, mouse and ferret DRD4 gene cDNA to amplify the corresponding horse gene. The PCR products were ligated into a linear plasmid pMD17, and sequenced respectively. These sequences were aligned to a conting to get most sequence of the horse DRD4 gene. The horse DRD4 gene has four exons and three introns, and share above 75% similarity with human, mouse and dog. And by comparing the DRD4 gene sequence of six breeds, some variations among the sequence of six breeds horse DRD4 gene were detected in intron1 and exon3.