Objective: The study aimed to investigate the relationship between academic stress and extracurricular physical exercise among college students, with the goal of providing evidence and reference for effectively alleviating academic stress. Methods: A stratified cluster random sampling method was employed, along with the Chinese College Student Psychological Health Screening Scale and a self designed questionnaire. In January 2023, an online survey was conducted among 1 108 college students from eight colleges and universities in Jiangsu Province. Statistical analyses included independent samples t test, one way analysis of variance (ANOVA) and the optimal scale regression model. Results: It revealed that 50.8% of students worried about falling behind their peers in their studies, 51.7% expressed concerns about exams, 21.7% exerted significant effort but still struggled to keep up with the pace of learning, and 24.9% felt difficulties in their studies. The overall index of academic stress was higher among undergraduate institutions, first year students, female students, and urban residents ( t/F =3.66, 10.96, -5.46, 3.52, P <0.01). The average time of weekly extracurricular physical exercise for students was (2.35±2.18)h, and there were significant differences by gender, only child status, and grade groups( t/F =2.35, 4.66, 7.09, P <0.05). The optimal scale regression model analysis ( R 2=0.17, F=32.03, P <0.01) revealed that the regression coefficient and partial correlation coefficient between academic stress and extracurricular physical exercise time were both -0.33( P <0.01). The importance of extracurricular physical exercise in the model was 0.66, with a tolerance value of 0.97. The regression coefficients and partial correlation coefficients for academic stress and extracurricular physical exercise time were -0.35, -0.35 for undergraduate students, and -0.31, -0.32 for junior college students ( P < 0.01 ). Conclusion A significant number of college students experience varying degrees of academic stress, and their engagement in extracurricular physical exercise is insufficient. There is a negative association between academic stress and extracurricular physical activity time among college students. Universities should encourage students to increase extracurricular physical activity time to reduce academic stress and promote college students mental health.