The aim this study was to examine the effect of general squat and wall squat exercises on the muscle activity of the vastus medialis oblique (VMO) and vastus lateralis (VL), and the muscle activity of the VMO and VL during squat exercises depending on the flexion angle of the knee joint. Thirty adults in their 20s participated in the study, and subjects were divided into the general squat group, and the wall squat group, and their electromyographic (EMG) was monitored and collected during squat exercises. The muscle activity of the VL during squat exercises was compared between the two groups, and that of the wall squat group was higher than that of the general squat group, indicate a statistically significant difference (p<.05). The muscle activity of the VMO of the wall squat group was also higher than that of the general squat group, indicate a statistically significant difference (p<.05). The muscle activity depending on the angle of the knee joint was compared between the two groups, and that of the VL showed a statistically significant difference between different angles of the knee joint (p<.05). That of the VMO also showed a statistically significant difference between different angles of the knee joint (p<.05). The findings of the present study suggest that wall squat is more effective in improving the muscular strength of the VL and VMO than general squat, and that maintaining the angle of the knee joint at 60° is more effective in improving the muscular strength than maintaining it at 15° or 45°