•Live streaming in OHC enhances patients’ understanding about physicians.•Physicians’ faster, quality responses in live increase patient subscriptions.•More physician subscribers positively correlate with increased paid consultations. Live diagnosis is an application of live streaming in online health communities, through which physicians share knowledge and interact with patients in real time. Live videos enable patients to evaluate physicians comprehensively before a paid consultation. By applying dual-process theory, we examine the relationships between physicians’ speech features, demographic characteristics, the information quality of live content in live videos and patients’ subscription and consultation behavior. Data from 992 physicians who provided live diagnoses were collected from an online health community. Results show that physicians’ speech features and live content quality are significantly associated with patients’ subscription behavior, which is further associated with their online consultation behavior. This study provides a new perspective for investigating patients’ consultation behavior in the online health community context. It enriches the application of dual-process theory, and offers implications for physicians and online health community administrators in providing better live diagnosis services.