Objective : The purpose of this study was to analyze the effects of lower limb muscle activity on postural stability and ground type in elderly women subjects· Method : Forty two subjects participated in the experiment (high group - age: 74·29±4·13 yr, height: 152·44±5·54 cm, weight: 57·43±6·16 kg, BMI:24·77±2·99, low group - age: 77·67±5·16 yr, height: 151·40±3·93 cm, weight: 60·92±6·40 kg, BMI: 26·59±2·57)· Wireless EMG with eight channels wasused· Ground types were classified as flat and cushion· Results : In the double-support phase, left and right rectus femoris, left biceps femoris, left and right tibialis anterior, and left gastrocnemius did not showa significant difference in postural stability according to ground type· However right biceps femoris and gastrocnemius showed higher muscle activity inthe elderly women group with lower postural stability· In the single-support phase, left and right rectus femoris, right biceps femoris, and left and righttibialis anterior did not show a significant difference in postural stability according to ground type· In addition, left biceps femoris had higher muscleactivity in the elderly women group with lower postural stability· Left gastrocnemius had higher muscle activity in the elderly women group with higherpostural stability and right gastrocnemius had higher muscle activity in the elderly women group on cushion ground· Conclusion : In a dynamic postural stability and cushion ground, biceps femoris and gastrocnemius muscle activity were high· As a result, biceps femorisand gastrocnemius muscle strengthening exercise on cushion ground could be beneficial in the prevention of falling·