In the context of the implementation of the National Fitness Program, and with fitness games as a medium, the work aims to study the main influencing factors on users' self-efficacy, explore the design methods of fitness games, and help users optimize their fitness experience. The degree of internal correlation between the above elements and self-efficacy was analyzed by structural equation modeling from the six aspects of technical quality, functional quality, social interaction, fun, ease of use and usefulness. 482 questionnaires were distributed, data were collected through the questionnaire scale, and reliability analysis was performed using SPSS software to ensure that each indicator met the matching standard. Through the research on the model path coefficient, it was found that the factors that directly affected user self-efficacy included functional quality, usefulness, and ease of use, among which usefulness had the most significant positive impact on self-efficacy. In addition, the technical quality and social interaction elements of games indirectly enhanced user self-efficacy. The technical quality of fitness games is the foundation of development and design, and ensuring the practicality, ease of use and functional quality of the game is the key to effectively improving users' self-efficacy when using fitness games.