In this study, changes of muscle activity that occurs when subjects walk or go up and down the stairs were analyzed by using EMG signal. The muscle activity of swing phase and stance phase was evaluated for each walking. Five healthy male capable of normal gait and stair climbing were selected as subjects. EMG signal from quadriceps and biceps femoris was measured. The stance phase was high during walking and the swing phase was high when subject go up the stairs, when subject go down the stairs, the stanse phase was high. Observations of muscle activity, stanse and swing phases were separated easily but kinds of gait were not separated. Through this study, appropriate EMG measurement part can be selected and recognition of stance and swing phased is possible using muscle activity when developing rehabilitation content for patients with transtibial amputation.