Focusing on the context of short-video platforms, this study takes Stuart Hall’s Encoding/Decoding Theory and the Uses and Gratifications Theory as the core theoretical support, reconstructs the measurement dimensions of “athletic identity” by integrating the Athletic Identity Measurement Scale (AIMS), and constructs a theoretical model of “Athletic Identity → Short-video Symbol Exposure → Decoding Effect”, incorporating regional cultural familiarity and group type as moderating variables. The study defines core concepts: athletic identity includes four dimensions—athletic identity cognition, emotional connection, value identification, and behavioral tendency; short-video symbol exposure focuses on the initiative of exposure, frequency, and interaction depth; decoding effect covers symbol recognition, understanding of translation logic, resonance with sportsmanship, and willingness to interact and disseminate. Through theoretical deduction, hypotheses are proposed: athletic identity positively influences symbol exposure behaviors (e.g., individuals with a strong emotional connection are more proactive in exposure); symbol exposure further enhances the decoding effect (e.g., high-frequency exposure strengthens resonance with sportsmanship); and symbol exposure plays a complete mediating role. Additionally, there are significant moderating differences in the dissemination effect paths between audiences from Guangdong, Hong Kong, and Macao, as well as between ordinary audiences, disabled audiences, and UGC creators.