Objective To compare the difference of muscle strength of lower limbs between 10~11 years old boys who take football exercise in long time and who don't take football exercise. Methods A total of 60 boys who have similar height and weight were divided into two equal groups,and one group who had two years football exercise as football exercise group and the other group without football exercise as control group,the tests on flexion and extension model of hip joint,knee joint and ankle joint of two groups were done by using Germen IsoMed 2000 isokinetic dynamometer. Results 1)The peak torque of football exercise group which get hip joint flexion(t=1.314),extension(t=1.972),knee joint flexion(t=1.897),ankle joint extension(t=1.128),were larger than the control group,but not significant (P>0.05).2)The peak torque of football exercise group who get knee joint extension (t=-5.812),and ankle joint flexion (t=3.064),were significantly larger than control group (P<0.01). Conclusion To boys,long football exercise can significantly improve the strength of knee joint extensor,ankle joint flexor and slightly improve the strength of hip joint flexor and extensor.