Objective To establish an evaluation index system for the quality and safety of day surgery, and provide standard and professional quantitative bases for monitoring and management of day surgery quality. Methods From December 2021 to May 2022, based on the frame work of the three-dimensional “structure-process-outcome” quality model, two rounds of Delphi method interviews were conducted with 15 day surgery-related management experts, and analytic hierarchy process was used to calculate the weight of each index. Results The effective questionnaire recovery rates of the two rounds of surveys were both 100%; the expert authority coefficients were 0.94 and 0.98, respectively; the variation coefficients were 0.00-0.30 and 0.00-0.24, respectively; the Kendall coordination coefficients were 0.382 (P<0.05) and 0.266 (P<0.05), respectively; and the consistency ratios of all levels were less than 0.1. The final day surgery quality and safety evaluation index system included 3 first-level indicators, 10 second-level indicators, and 43 third-level indicators. Conclusions The quality and safety evaluation index system of day surgery is scientific, reasonable and comprehensive. It can provide a reference for the quality and safety evaluation of day surgery and solidly promote the high-quality development of public hospitals.