Objective To observe the effects of ticagrelor and a double dose of clopidogrel on the incidence of cardiovascular ischemia and bleeding after percutaneous coronary intervention (PCI) in the elderly patients with mutant CYP2C19. Methods Enrolled in this study were patients with mutant CYP2C19, who underwent PCI in the Department of Cardiology of Chinese PLA Hospital No.309. They were randomly divided into clopidogrel group and ticagrelor group, with 120 in each group. The former took aspirin and a double dose of clopidogrel and the latter aspirin and ticagrelor. Major adverse cardiovascular events (MACEs) and bleeding events were observed during the hospital stay and a follow-up of 12 months. Data were processed using SPSS statistics 17.0. Depending on data type, Student′s t-test or Chi-square test was conducted for the comparison between two groups. Results Compared with the clopidogrel group, the ticagrelor group had significantly higher R-value [(24.2±2.8) vs(15.3±2.4)s] and K-value [(13.4±2.6) vs(6.6±1.8)s], but lower MA [(46.2±2.1) vs(69.5±3.2)mm], the differences being statistically significant (P<0.01). The incidence of MACEs in the ticagrelor group was significantly lower than that in the clopidogrel group [13.3%(16/120) vs 32.5%(39/120), P<0.01]; however, there was no significant difference in the incidence of bleeding events between two groups (P>0.05).Conclusion In the patients with mutant CYP2C19, a double dose of clopidogrel can be effective in platelet inhibition but with high cardiovascular ischemic events; ticagrelor can effectively reduce drug resistance, enhance platelet inhibition, and thus decrease the incidence of cardiovascular ischemic events.