Gastric ulcer is a chronic digestive disorder characterized by recurrence, complications, and reduced quality of life. Although pharmacological treatment remains essential, variability in nursing processes, incomplete risk identification, and insufficient follow-up may hinder recovery and long-term disease control. Root cause analysis (RCA) is a structured quality-improvement method used to identify underlying causes of care-related risks and to guide targeted corrective action. This article describes a reproducible RCA-based risk management nursing workflow for hospitalized patients with gastric ulcers. In this retrospective comparative implementation, 240 patients admitted between January 2021 and December 2024 were identified from hospital records and classified, according to the nursing model documented during hospitalization, into a routine-care group and an RCA-based nursing group, with 120 patients in each group. The workflow includes multidisciplinary team formation, identification of representative nursing risk events, timeline reconstruction, root-cause classification, individualized intervention planning, dynamic inpatient reassessment, discharge education, and structured post-discharge follow-up. Outcome assessment procedures include evaluation of nursing effectiveness, complications, recurrence, patient satisfaction, and quality of life using gastroscopy, hospital records, a structured satisfaction assessment, and the Short Form-36 (SF-36). In this retrospective comparative study, patients managed under the RCA-based workflow showed more favorable outcomes than those receiving routine nursing care. This protocol provides an operational framework for integrating RCA into gastric ulcer nursing practice and may support reproducible risk management in other chronic disease care settings.