Purpose The purpose of this study were how to effect gait ability to chronic stroke patients who were taken knee extensor fatigue and were understood and offered the way of effective therapy to stroke patients in clinical trials. Methods The subject of this study were 16 chronic stroke patients (9 males, 8 females), and 16 healthy volunteers(5 males, 11 females) and their average duration of symptoms were 4.9 years at S hospital in Sungnam city. Stroke patient group age was 55.67, health group age was 59.13. Both stroke patient group and healthy group were measured using maximal voluntary isometric contraction(MVIC) for leading knee extensor fatigue. Isometric contraction was maintained for 10 seconds. And each isometric contraction was taken rest 5 seconds one time for inducing muscle fatigue. The end point was measured decreasing 3 times continuously which the value of MVIC was less 50%, and then the number of knee extensor to induce muscle fatigue gait ability were measured after taking knee extensor fatigue. Results There was a significantly differences that Stroke patients group was shown that the paretic side knee extensor fatigue was represented faster than health control group (p<0.05). The gait ability were represented drastically decreased knee extensor fatigue in Stroke patients group’s non paretic side. Conclusion Therefore, localized muscle fatigue by gaiting abnormal gait pattern to chronic stroke patient was affected the disability of gait capacity. And abnormal gait pattern was brought secondly increasing number of falling down. These factors were considered to stroke rehabilitation.