Purpose : The purpose of this study was to compare the Effects of Knee Extensor, Flexor Muscle Strength and Joint Position Sense in Squat Exercise on Variety Surface. Method : Subjuects were consisit of 30 male and female who had non disorder knee joint. we had devided 3 group(control group, balance pad group, and togu group) and we measured that knee joint $15^{circ}/45^{circ}$proprioception(position sense) and Peak Torque of knee extensor, flexor muslce at $60^{circ}/sec$, $180^{circ}/sec$ angular velocity. Result : First, knee joint $15^{circ}$proprioception(position sense) of balance pad and togu group was significantly different after exercise(p<.05), but only balance pad group was significantly different at knee joint $45^{circ}$. Second, knee extensor Peak Torque of balance pad and togu group was significantly different at $60^{circ}/sec$, $180^{circ}/sec$ angular velocity(p<.05). Third, knee flexor Peak Torque of balance pad and togu group was significantly different at $60^{circ}/sec$, $180^{circ}/sec$ angular velocity(p<.05). Conclusion : Squat exercises on the balance pad and togu were affects knee joint proprioception and muscle strength improvement. These results suggest that squat exercise on the unstable surface is effective for prevention of knee joint injury and functional activity.