For Destination Marketing Organizations (DMOs), the use of social media marketing has become their most important marketing tool.This paper discusses the online marketing process of cultural tourism through the thematic analysis method, and reveals the online marketing content of cultural tourism from three stages: pre-tour marketing, in-tour marketing and post-tour marketing.Research shows that the marketing of cultural tourism on social media is mainly through the self-established IP of tourism-related stakeholders and tourists to automatically generate or forward high-quality cultural tourism content, generate certain influence and attract a group of fans, from which trust can be built by interacting with uploaders. The results imply that the high quality cultural tourism content is the key to the success of online marketing, therefore, both the tourism destination organizations and the tourism enterprises should do a good job in the content generation