With the COVID-19 outbreak, there is an increasing focus on sports and fitness needs. Due to the need of epidemic prevention and control, fitness at home has gradually become a popular lifestyle. With the rapid development of smart phone application technology, artificial intelligence and Internet of Things, many enterprises have developed sports and fitness apps. These apps provide training courses for users, and customizes personalized training plans for them in combination with smart wearable devices. Keep App, a sports and fitness app developed by Keep Company, has the most users in China at present. It has created a technology platform for users to experience smart sports at home from multiple aspects, and has gained considerable income in operation. Taking Keep company as an example, this paper analyzes the marketing environment of the sports and fitness industry by using PEST model and Porter’s Five Forces model, and puts forward optimization suggestions for Keep company’s marketing strategy from the aspects of customer’s need strategy, customer’s cost strategy, convenience strategy and communication strategy by using 4C marketing theory.