The improvement of learning motivation is of great significance to the development of ubiquitous learning habits and the deepening of the lifelong learning concept. With the increasingly perfect functions of the mobile social network platform, in order to meet the needs of learning society construction and lifelong learning, the application mode of “social + education” is becoming more and more mature. However, learners’ learning status and learning motivation are not the same on mobile social network platforms. Therefore, it is of great importance to identify factors affecting learners’ learning motivation on mobile social network platforms and propose improvement paths for them. In this research, from the TC model, the learner’s learning motivation model based on the mobile social network platform is established and followed by some relevant hypotheses. Structural equation model (SEM) and fuzzy-set qualitative comparative analysis(fsQCA) are combined to explore the factors influencing learner’s learning motivation and relative improvement paths. The research finds that factors including attitude, need, emotion and ability have a positive impact on learners’ learning motivation, while stimulation has no significant impact and reinforcement has a negative impact. Therefore, it suggested that the platform should avoid replicating traditional pattern reinforcement strategies and adopt corresponding learning motivation enhancement strategies for four different types of learners: learners with strong learning purpose, learners who pay attention to the learning experience, active learners and passive learner.