This study investigates key factors influencing the users' intention to pay for online medical service via the online platform performance and trust. A data sample of 312 is gathered via a questionnaire survey, with analysis performed via partial least squares structural equation modeling. Results portray a new perspective within the context of internet usage research for online medical service platform adoption and use behaviors. Briefly, the information quality, system quality, and convenience of the platform are found to affect the perceived benefit of users significantly. Among other findings, users' perceived reliability of the platform also positively affects doctor reliability and the users' intention to pay whereas doctor reliability positively affects the users' intention to pay. Moreover, the misdiagnosis risk positively regulates the relationship between the users' trust tendency and doctor reliability. Finally, the timeliness of the response of the platform also moderates positively the relationship between doctor reliability and the users' intention to pay.