As the application of social media in tourism growing rapidly, shared information on social media is recognized as an important information source for both tourism suppliers and potential tourists. This study constructs a conceptual framework why tourists share their travel experiences on social media based on the theory of reasoned action and the self-determination theory, and tests four conceptual foundations in the framework: intrinsic motivation, extrinsic motivation and face orientation which contains protective face and acquisitive face. Data were collected through an online survey and the research model was tested with 353 respondents who were social media users. The results indicate that protective face was observed to negatively moderate the relationship between both intrinsic as well as extrinsic motivations and sharing intention respectively, while the moderating effect of acquisitive face is significant on neither. Our findings extend prior literature, and offer a theoretic guidance to tourism industry on how to improve business through social media.