This study is about to evaluation of postural stability according to characteristics of electrical stimulation on the ankle muscles. We measured body sway(center of pressure, COP) when various parameters of electrical stimulation was applied to ankle muscles in stable and unstable posture. Subjects consisted of 10 young adults, and electrical stimulation was delivered on right and left of tibialis anterior and Achilles tendon. The body sway was measured during electrical stimulation of three duty cycle and frequencies in stable posture and three amplitudes of sensory threshold in unstable posture. Consequently, the COP Shift is higher during electrical stimulation of 1/30(duty ratio) and 100Hz(frequency) in stable posture. In unstable posture, 100% amplitude of sensory threshold induced postural stability. These findings are important for the rehabilitation system of postural stability and the use of electrical stimulation as somatosensory information.