With the rapid development of Internet technology and the popularity of social media, the interaction between brands and consumers has undergone profound changes. Social media platform, with its unique real-time, interactive and communication, has become an important bridge between brands and consumers. In the complex and changing market environment, brand building and maintenance is the key to the success of enterprises. With rapid changes in consumer behavior and market competition, brands need to adopt innovative strategies to strengthen their market position and consumer loyalty. The impact of KOL and KOC on consumers on social media platforms is complementary. KOL quickly increases brand awareness through extensive influence and professionalism, while KOC deepens consumers’ trust and desire to buy brands through authenticity and high interactivity. The combination of the two can form a complete marketing chain from awareness promotion to trust establishment to purchase transformation to maximize the marketing effect. This paper aims to explore how brand interaction on social media platforms affects consumers’ purchase decision-making process, and analyze its mechanism, influencing factors and effects, and give suggestions.