Objective: To explore the micro associations and key bridge nodes between physical fitness indicators and anxiety/depressive symptoms among college students using network analysis, so as to provide a theoretical foundation for promoting physical and mental health of college students. Methods: From September to October 2025, a combination of purposive sampling and cluster sampling was employed to select 2 158 college students from three universities in Xuzhou City. Seven physical fitness indicators were measured and standardized according to the National Student Physical Health Standard. The Generalized Anxiety Disorder Scale-7 (GAD-7) and the Patient Health Questionnaire-9 (PHQ-9) were used to assess anxiety and depressive symptoms. Independent samples t-test was used for intergroup comparisons of physical fitness indicators and psychological symptom scores. A gaussian graphical model (GGM) was constructed to calculate node and bridge strength, followed by stability analyses. Results: The detection rates of anxiety and depressive symptoms among college students were 21.3% and 24.5%, respectively. Male participants demonstrated superior performance in physical fitness indicators such as vital capacity, 50 meter sprint, and standing long jump compared to female participants, whereas females exhibited better results in the sit and reach test ( t =48.35, -44.82 , 70.21, -16.51, all P <0.01). Regarding psychological indicators, female participants showed higher scores of anxiety and depressive symptoms than males ( t =-4.15, -4.46, both P <0.01). Physical fitness and psychological symptoms were predominantly negatively correlated. "feeling tired" and "not being able to stop or control worrying" were the symptoms with the highest centrality in the network of physical fitness and phychological symptoms among college students (standardized strengths were 2.15 and 1.98, respectively). Among the bridge indicators, the "1 000 m (male)/800 m (female) run" exhibited the highest strength (0.85), outperforming "vital capacity" (0.35); it was linked to the symptom cluster primarily by negatively predicting "feeling tired" (edge weight=-0.38). The network stability was excellent of physical fitness and phychological symptoms among college students (correlation stability coefficient= 0.60 ). Conclusions Endurance capacity serves as the most critical bridge connecting physical and mental health, and its decline is closely related to intensified feelings of fatigue. Colleges should prioritize endurance training as a core target for promoting college students mental health.