Psychological issues have a complex and multidimensional impact on a college athlete's training and performance. As the reserve talent of competitive sports, it is very important to investigate the psychological health of athletes. This study aims to explore the association between generalized anxiety disorder (GAD), post-traumatic stress disorder (PTSD), basic psychological needs (BPN), and mental health (MH) among Chinese college athletes. Chinese college athletes who were willing to participate in the study, had participated in national competitions, and had a Chinese athlete rating certificate were included in this study. Participants completed the Kessler Psychological Distress Scale (K10), the Generalized Anxiety Disorder Scale (GAD-7), the Impact of Event Scale-Revised (IES-R), and the Basic Needs Satisfaction in General Scale (BNSG-S). The study involved 665 college athletes (415 males and 250 females), with an average age of 20.43 years (SD = 1.68). We performed descriptive statistics, correlation analyses, and moderated chain mediation analyses using SPSS 22.0 and Hayes' PROCESS macro. The results of the final model showed that basic psychological needs were positively correlated with mental health ( = 0.443, < 0.001), while PTSD ( = -0.346, < 0.001) and generalized anxiety disorder ( = -0.527, < 0.001) were negatively correlated with mental health among college athletes. There were significant indirect impacts. According to the bootstrapping results, basic psychological needs and generalized anxiety disorder played a mediating role in 22.54% and 50.29% of the total effects of PTSD on mental health, respectively. Meanwhile, the chain mediating effect of basic psychological needs and generalized anxiety disorder (7.23%) was also significant. The study's findings advance our understanding of the connections between PTSD and mental health and highlight the significant roles played by basic psychological needs and generalized anxiety disorder in that link among Chinese college athletes.