Using Dongguan, a city characterized by high population mobility and the rapid development of digital health services, as the study setting, this study examines the determinants and underlying mechanisms of privacy disclosure behavior among residents with experience using Internet hospitals. Structural equation modeling and bootstrap analysis were employed. The results showed that actual privacy disclosure behavior differed significantly by gender, age, educational attainment, and occupation (P<0.05). Distributive fairness positively influenced perceived service benefits and platform trust, whereas procedural fairness positively influenced perceived privacy risk. Perceived service benefits and platform trust positively affected privacy disclosure intention, while perceived privacy risk had a negative effect. Platform trust was the strongest predictor of privacy disclosure intention (β=0.7918, P<0.001). Privacy disclosure intention, in turn, significantly predicted actual privacy disclosure behavior (β=0.9714, P<0.001). These findings indicate that fairness perceptions shape privacy disclosure intention through assessments of perceived benefits, platform trust, and privacy risks, which subsequently translate into actual disclosure behavior. Internet hospital platforms should enhance perceived service value, strengthen user trust, and improve privacy risk governance to promote the informed, voluntary, and appropriate disclosure of health information.