Dual antiplatelet therapy is recommended for coronary heart disease patients after percutaneous coronary intervention (PCI) so as to reduce the risk of major adverse cardiovascular events (MACE). However, some patients do not display adequate antiplatelet response and show resistance to clopidogrel, which seriously affecting the prognosis of them. Therefore, it is a practical problem for the relationship between CYP2C19 genetic polymorphisms and myocardial injury after PCI as well as long-term MACE. We reviewed the problem in this article.