With the continuous development of the economy and the increasing improvement of living standards, the fitness model of sports activities can no longer fully meet the needs of modern people by means of places and time. At the same time, China has vigorously supported the policy of "Internet plus", so sports and fitness software came into being. Keep App, as one of the popular software, has aroused widespread concern in society. The SWOT analysis method is used to study the interaction form, advantages, disadvantages, opportunities, and threats. It also analyzes the impact of para-social interaction on users' purchases. The conclusion is that appropriate interaction can bring positive stimulus to people's purchase intention. The research question is based on keep software to summarize and analyze the impact of people's interaction with sellers in the process of purchasing products. To get a better sales plan. The article will combine the para-social interaction theory to discuss.