Objective To analyze the current situation of the centralized treatment mode for daytime treatment (excluding daytime surgery) services in a large-scale military hospital, and provide practical support for the management and operation of the centralized treatment mode for daytime treatment. Methods Data on patients undergoing centralized daytime treatment in the Department of Ambulatory Medicine, First Medical Center of PLA General Hospital were retrospectively collected between February 7, 2021 and December 31, 2023. The patients’ condition, daytime treatment operation indicators, and quality control indicators were statistically analyzed. Results A total of 14903 patients underwent daytime treatment, including 8548 females and 6355 males. The patients’ age ranged from 18 to 74 years old. There were 9757 patients (65.47%) who had been hospitalized ≥ 2 times. The main payment method for patients was medical insurance (83.16%). Breast cancer accounted for the highest proportion (26.45%). The main treatment methods for patients were targeted therapy and immunotherapy (68.03%). The patients experienced a total of 1146 drug-related adverse reactions, mainly involving anti-tumor drugs. Among them, 15 cases were drug-related adverse reactions treated on the day of treatment, and the other 1131 cases were drug-related adverse reactions that occurred outside the hospital. After optimizing the entire process of daytime hospitalization (timed based treatment) in January 2023, compared to 2022, the average waiting time for patients after admission was reduced by 26.89%, the bed utilization rate increased by 9.09%, and patient satisfaction increased to 98.98%. In 2023, the default rate of daytime treatment was 1.15%, the cancellation rate of daytime treatment on the day of treatment was 4.39%, and the discharge follow-up rate reached 100%. Conclusions The daytime treatment under the centralized treatment mode in the the Department of Ambulatory Medicine, First Medical Center of PLA General Hospital focuses on breast cancer patients, and the main treatment methods are targeted therapy and immunotherapy. Time based treatment is beneficial for shortening the average waiting time of patients after admission, improving bed utilization and patient satisfaction.