Abstract: Objective To evaluate and analyze the impact of continuing preoperative angiotensin converting enzyme inhibitor（ACEI） or angiotonin receptor blocker（ARB） on perioperative cardiovascular and cerebrovascular events in elderly patients with hypertension undergoing emergency surgery. Methods A total of 723 elderly hypertensive patients, aged 60 to 96 years, American Society of Anaesthesiologist（ASA）ⅡE to ⅣE, who underwent emergency surgery during December 2022 to August 2023 were retrospectively screened. Patients were assigned to ACEI/ARB continuation or discontinuation on the day of surgeryusing 1∶1 propensity score matching method. Factors including gender, age, ASA classification, anesthesia method, primary disease, hypertension classification, history of cerebrovascular events, comorbid internal diseases, preoperative activity tolerance, regular medication use, history of coronavirus disease 2019（COVID-19） and prognosis were considered when matching by propensity score. The incidence of cardiovascular and cerebrovascular events（severe hypotension, malignant arrhythmia, myocardial infarction, stroke） and all-cause mortality within 6 months after operation were analyzed. Results A total of 206 patients were successfully matched. Among them, 117 patients（56.80%） suffered from severe hypotension during operation and within 24 hours after operation, including 82 patients（79.62%） in the ACEI/ARB continuation group and 35 patients（33.98%） in the ACEI/ARB discontinuation group. The cumulative duration of severe hypotension was significantly longer in ACEI/ARB continuation group than in ACEI/ARB discontinuation group15（5, 20） vs 0（0, 10） min; W=-3 160, P＜0.01. Subgroup analysis indicated that in the patients who were older（age＞75）, had preoperative activity tolerance ＜4 metabolic equivalent, had COVID-19 infection within 3 months, or underwent open surgery, ACEI/ARB continuation on the day of surgery led to an increased risk of severe perioperative hypotension compared to discontinuation. There were no statistically significant differences between the two groups in terms of the incidence of myocardial infarction and stroke, and all-cause mortality within 6 months after operation. Conclusions Continuing ACEI/ARB on the day of surgery significantly increases the risk of severe perioperative hypotension in elderly hypertensive patients undergoing emergency surgery. However, it has no significant impact on the incidence of myocardial infarction and stroke and all-cause mortality within 6 months after operation.