This study explored the effect of the coach–athlete relationship perceived by college athletes on athletic behaviour, examining the mediating effect of psychological needs. This study was conducted with 254 college athletes using questionnaires, and the research instruments included the Coach–Athlete Relationship Scale, the Psychological Needs Scale, and the Athletic Behaviour Scale. The results of the study were as follows: (1) the coach–athlete relationship perceived by student-athletes had a direct positive and significant effect on athletic behaviours (β = 0.268, p < 0.001, and direct effect = 0.0344); and (2) psychological needs had a significant mediating effect between the coach–athlete relationship and athletic behaviours (indirect effect = 0.2433), and the mediating effect percentage was 41.56%. The overall mediation effect value was 0.5854. The findings of the study emphasized that, by improving the coach–athlete relationship, it could help to improve the psychological needs of college athletes and, thus, promote their positive motor behaviours. In the coach–athlete relationship, the effect of closeness on the promotion of motor behaviour was particularly significant, in which special attention and emphasis should be given to the closeness between coaches and athletes in a practical implementation. Subsequently, coaches should focus their training on enhancing the coach–athlete relationship as a crucial part of training in order to perform well in competitions.