Objective: To explore the current status of knowledge, attitude and behaviour (knowledge, belief and action) of rational use of medication for vaginitis in gynaecological outpatients and their influencing factors, and to provide a basis for the development of targeted interventions. Methods: A convenience sampling method was used to select 400 patients with vaginitis admitted to the gynaecology outpatient clinic of a tertiary care hospital, and demographic characteristics, knowledge, belief and behaviour data were collected through a self-administered questionnaire, and structural equation modelling (SEM) was used to analyse the knowledge, belief and behaviour pathway relationships. Results: The patients’ scores for rational drug use knowledge is 65.32 ± 12.45 points, attitude score is 38.21 ± 7.33 points, and behavior score is 41.15 ± 10.27 points. The results of single factor analysis and multiple linear regression analysis indicate that education level has a significant impact on all three dimensions of knowledge, belief, and action, and is one of the most important influencing factors. SEM shows that the path coefficient of knowledge to behavior is 0.42, attitude to behavior is 0.50, and knowledge to behavior is 0.16. Education level has a significant positive impact on knowledge, attitude, and behavior, with path coefficients of 0.35, 0.30, and 0.27, respectively. Conclusion: The rational medication behavior of gynecological outpatient patients with vaginitis is influenced by both knowledge and attitude, and it is necessary to strengthen health education and medication guidance.