Lesson study has been recognised as one of the most effective teacher professional development programmes. In China, technology-supported online lesson study (OLS) switches the traditional face-to-face LS to a virtual format. This paper seeks to explore the ways in which Chinese OLS promotes professional development among teachers and contributes to educational equity. Based on an introduction to the key characteristics of Chinese OLS, drawing upon existing literature and empirical data, together with a comprehensive review of Chinese OLS models, the research findings suggest that Chinese OLS greatly fosters teachers' pedagogical collaboration and enhances their digital competence regardless of geographical limitations and scheduling constraints. It also significantly contributes to bridging the educational quality gap between urban and rural schools through the establishment of online communities. Present research findings about experiences of Chinese OLS indicate that a robust teaching research culture, substantial support from the Chinese government and guidance of knowledgeable others (KOs) are all indispensable for the operation and integration of OLS in China. Building on these findings, further explorations are required to emphasise the emotional ties among teachers in a virtual community, cultivate teachers' positive attitudes towards technology, and form interdisciplinary OLS teams with diverse expertise and perspectives.