Objective. To explore the effect of percutaneous coronary intervention (PCI) standardized telephone follow-up service mode on out-of-hospital complications, rehospitalization rate, and life quality of discharged acute coronary syndrome (ACS) patients after PCI. Methods. From August 2020 to March 2022, 218 ACS patients who were discharged after PCI were included. The controls accepted routine nursing care, and the researches accepted PCI standardized telephone follow-up service mode. The nursing satisfaction, rehospitalization rate, out-of-hospital complication rate, blood lipid level, and life quality score were taken as the comparisons. Results. The nursing satisfaction of study group (100.00%) was significantly higher than that of control group (88.07%). The rehospitalization rate was dramatically lower in the study group (3/109; 2.75%) than in the control group (25/109; 22.94%) ( P < 0.05 ). In addition, compared with the control group, the incidence of complications (acute myocardial infarction and angina pectoris) was significantly reduced in the study group outside the hospital ( P < 0.05 ). The blood lipid levels of TCHO, TG, LDL-C, and HDL-C were lower in the study group than in the controls. Further, after nursing, the quality of life score of the two groups was both decreased with a higher quality of life score in the study group ( P < 0.05 ). Conclusion. The application of PCI standardized telephone follow-up service mode in discharged patients with acute coronary syndrome after PCI can reduce out-of-hospital complications and rehospitalization rate and improve blood lipid level and life quality.