Background: The purpose of this study was to a comparison of physical fitness according to the body mass index (BMI) of Chinese college students. Design: Cross-sectional study. Methods: According to the BMI, the research objects are divided into four types: underweight, normal weight, overweight, and obesity. This research took 26,976 college students who participated in Jiujiang College. It examines BMI, 50m, vital capacity, standing long jump, sitting forward bend, sit-up (female), pull-up (male), 800m (female), 1000m (male) which is to research the correlation between different BMI and other indicators. Results: The physical qualities of students with normal weight are significantly better than those with other BMI groups. Pearson correlation analysis showed that male BMI was positively correlated with vital capacity (r=0.07, p<0.01), 50m (r=0.15, p<0.01) and 1000m (r=0.14, p<0.01), and negatively correlated with standing long jump (r=-0.12, p<0.01), sitting forward bend (r=-0.06, p<0.01) and pull-up (r=-0.13, p<0.01); Female BMI was positively correlated with vital capacity (r=0.03, p<0.01), 50m (r=0.21, p<0.01) and 800m (r=0.18, p<0.01), and negatively correlated with standing long jump (r=-0.07, p<0.01), sitting forward bend (r=-0.11, p<0.01) and sit-up (r=-0.10, p<0.01). Conclusion: Overweight and underweight will affect the physical quality of college students. Students should keep their BMI within the normal range for their health.