With the rapid development of social media, people’s lives have changed in many areas. And in the business area, social media has gained tremendous fame as an effective channel for marketing. More and more brands created official social media accounts and spent a lot of money on social media marketing. To explore the factors that affect the communication effect of social media marketing content, this paper systematically arranged prior research about social media marketing and live commerce, and then presented a conceptual model on the communication effect of social media marketing content. Based on the “5W” theory in communication studies, the conceptual model focused on how communication content affected the communication effect and explored the cross-layer moderating effect of communicator characteristics. And it is found that 1) followers’ number of communicators has the positive moderating effect on the content that encourage engagement between number of users covered; 2) professionalism of communicators has the positive moderating effect on the brand ambassadors’ information of content between interactions among users.