Objective：To investigate the relationship between CYP2D6*10 gene C188T single nucleotide polymorphism and metoprolol efficacy in elderly patients in the perioperative cardiac protection. Methods：Totally 323 elderly patients were screened out before surgery and single nucleotide polymorphism of CYP2D6*10 gene C188>T site was analyzed by PCR-RFLP method. After metoprolol treatment，incidence of hemodynamic instability during perioperative period and changes in troponin levels at 3 h after drug administration were observed. Results：C and T alleles frequencies were 48.76% and 51.24% in all patients，respectively. The wild-type homozygotes C/C，heterozygous C/T，mutant homozygous T/T genotype frequencies were 24.76%，47.98%，27.24%. All the frequency distribution was accord with the Hardy-Weinberg equilibrium. Statistical results showed that genotypes were moder－ately associated with postoperative cardiovascular surgery. CYP2D6*10 genetic polymorphisms showed that CYP2D6 genetic polymor－phism were associated with increased cardiovascular risk in a dose depended manner. Conclusion：CYP2D6*10 gene polymorphism（C188>T） mutation may lead to reduced metabolism of metoprolol in elderly patients during the perioperative protection. CYP2D6*10 mutation and the efficacy of metoprolol is closely related，which can significantly change systolic blood pressure of patients after drug administration. Doctors should be concerned about the impact of CYP2D6 genetic polymorphism on the efficacy of metoprolol in the future.