Purpose This study was conducted to know how task oriented stair walking training (forward, backward and sideway) has an effect on muscle activities in the lower extremity and the balance ability, and to suggest an approach to improve the ability of stroke patients. Methods 12 hemiplegia patients who were diagnosed with a stroke participated in the study. The subjects were assigned randomly to either an experimental group or a control group. Participants in the experimental group received a task oriented stair walking training (forward, backward, sideway) for 30 minutes. The control group received a balance training on the mat for 30 minutes. Both groups received each training for 5 times per week, for 5 weeks. Muscle activities were measured by EMG in both affected and nonaffected tibialis anterior (TA), rectus femoris (RF), biceps femoris (BF). The balance ability was measured using a Berg Balance Scale (BBS), Timed “Up and Go” (TUG) and Functional Reach Test (FRT). Results There were numerically increased muscle activities in both groups. However, there was no significant difference in muscle activity change. There were significant increases (p<.05) in BBS, FRT in both groups. The experimental group showed a significantly decrease (p<.05) and the control group was numerically decreased but there was no significant difference in TUG. But there is no significant change between two groups. Conclusion With that reason, the intervention was considered to have an impact on not only improvement of static functional balance but also improvement of dynamic mobility.