Brand-related user-generated content can reduce purchase uncertainty and influence consumers’ brand attitude and purchase decisions. Numerous studies have analyzed the content characteristics of brand-related user-generated content, yet the content's appeals have not been fully discussed. Based on the brand-related user - generated content data of skincare products from Xiaohongshu App, this study explores the impact of brand-related user-generated contenfs functional appeal on consumers’ social media engagement. In addition, we use Heuristic - Systematic Model to understand the bias effect between the physical attractiveness of the profile picture and the functional appeal. The study finds that the functional appeal of brand- related user-generated content has a significant positive impact on consumers' social media engagement. The more functional contents the brand-related user-generated content contains, the higher the consumers’ social media engagements will be. The users' physical attractiveness of the profile picture plays a positive moderating role. The more attractive the profile picture is, the stronger the impact of brand-related user-generated contenfs functional appeal on consumers' social media engagement will be.