Introduction: With the development of society, people's lift quality is gradually improved, which leads to increased social competition pressure. Meanwhile, undergraduate students are facing great pressure and serious mental health problems. Some college students' mental illness can be effectively treated by sports, which has been widely recognized by society. From the perspective of football, this study analyzes the specific impacts of football on the rehabilitation of college students' mental illnesses. Subjects and methods: This paper selects students from a university in Liaoning Province, China as the research subjects. The subjects are randomly divided into two groups. The experimental group is given relaxation therapy, supplemented with football exercise. The control group is only given relaxation therapy. The SCL-90 scores of each group are re-tested every ten days. The paper adopts correlation analysis, variance analysis, regression analysis, and other research methods. Results: Relaxation therapy positively affects the rehabilitation of college students' mental illness. Supplemented with football exercise, the rehabilitation effect is significantly improved. On the last time of the test, the arithmetic mean of SCL-90 scores in the experimental group is 162.42, which reaches the normal level. The results of the sample t-test show that the SCL-90 scores of the experimental group and the control group are significantly different at the level of 0.01 (t = -3.933, P = 0.008 < 0.01). Conclusions: Football exercise has an important impact on the rehabilitation of patients with mental illness. The causes of mental illness among college students are complex. To alleviate this problem, schools and all sectors of society shall take relevant measures to play their guiding roles in this regard.