Consumers today are individuals who fulfill life needs such as shopping using e-commerce. In its fulfillment, consumers can change in terms of purchasing decisions from one e-commerce to another e-commerce. This requires the company to always have a good strategy to compete in a healthy manner in terms of business. To learn about the importance of social media marketing activity, this study will find out how much influence the social media marketing activity received by e-commerce companies has on brand equity, customer relationships and repurchase intention. In addition, the study will learn how much influence brand equity and customer relationship have on an e-commerce company's repurchase intention. In this study, the survey is conducted by distributing questionnaires to respondents online where the research sample has several questions related to the habits and behavior of respondents. This research uses a sample of 210 people who are domiciled in Indonesia. In the research model, the study uses Structural Equation Modeling (SEM) analysis and the software used for this research is IBM SPSS AMOS. The results of the influence of social media marketing activities have the largest positive influence on customer relationships, brand equity is the main and biggest factor that positively and significantly affects repurchase intention in this research model. The accumulated experience and knowledge of consumers about a brand is a factor that can influence consumers to repurchase the same brand. Brand equity not only provides immediate benefits, but also long-term benefits by retaining consumers to continue to repurchase their products. A strong brand will make consumers always remember the brand. The study explains that customer relationships do not have any significant effect on repurchase intention. The main function of customer relationships at first and now is to try to reach their consumers more broadly, especially related to purchases, but this is not proven in repurchases, especially in this study. Customer relationships in the study did not have any significant effect on repurchase intention.