Abstract: Background　Kinesiophobia during the rehabilitation period of military training injuries in grassroots soldiers affects recovery outcomes and is intricately interrelated with pain, pain catastrophizing cognition, and social support factors, but the underlying mechanisms remain unclear. Objective　To explore the interaction mechanisms among pain, pain catastrophizing, perceived social support, and kinesiophobia during the rehabilitation period of military training injuries in grassroots soldiers using a structural equation model, and provide theoretical reference for psychological interventions during the rehabilitation period. Methods　A convenience sampling method was used to select 627 grassroots soldiers in the rehabilitation period of military training injuries from 15 grassroots units between October 2024 and March 2025 as research subjects. Data were collected using a general information questionnaire, the Tampa Scale for Kinesiophobia (TSK), the Visual Analogue Scale (VAS), the Pain Catastrophizing Scale (PCS), and the Perceived Social Support Scale (PSSS). A structural equation model was constructed to analyze the path relationships among the variables. Results　Among the 627 participants, the TSK score was 33(23 ~ 38) points, and the prevalence of kinesiophobia was 32.22% (202/627). The structural equation model revealed that pain (β=0.202) and pain catastrophizing (β=0.397) exerted significant positive effects on kinesiophobia. Perceived social support showed no direct effect (P= 0.717), yet influenced kinesiophobia through three negative indirect pathways, via pain (β=−0.041), via pain catastrophizing (β= − 0.079), and via the sequential "pain → pain catastrophizing" chain (β = − 0.023). Additionally, pain was found to indirectly contribute to kinesiophobia by increasing pain catastrophizing (β=0.112), demonstrating a significant mediation effect in the model. Conclusion　Kinesiophobia during rehabilitation among grassroots soldiers is primarily driven directly by pain and pain catastrophizing, while perceived social support exerts protective effects indirectly by alleviating pain and catastrophic cognitions. These findings provide empirical support for developing intervention strategies centered on enhancing social support, modifying catastrophic thinking, and optimizing pain management.