The pelvic compression belt (PCB) contributes to improving sacroiliac joint stability, and it has been used as an additional therapeutic option for patients with sacroiliac joint pain (SIJP). This study aimed to investigate whether the muscle activation patterns of the supporting leg was different between asymptomatic subjects and subjects with SIJP during one-leg standing, and how it changes with the PCB. 15 subjects with SIJP and 10 asymptomatic subjects volunteered to participate in this study. Surface electromyography (EMG) data (reaction time [RT] and muscle activation) were collected from the internal oblique, lumbar multifidius, gluteus maximus and biceps femoris muscles during one-leg standing with and without the PCB. Without the PCB condition, in the SIJP group, the biceps femoris muscle showed the fastest RT among all muscles (p<.05), whereas in the asymptomatic group, the RT of the internal oblique muscle was the most rapid (p<.05). In condition without the PCB, the biceps femoris EMG amplitudes in the SIJP group were significantly greater than that in the asymptomatic group (p<.05). After the application of the PCB, the RT of the biceps femoris muscle was significantly increased only in the SIJP group (p<.05). Moreover, the biceps femoris EMG amplitudes significantly decreased and the gluteus maximus EMG amplitudes significant increased only in the SIJP group by applying the PCB (p<.05). However, this had no such effect on the gluteus maximus and biceps femoris EMG patterns in the asymptomatic group (p>.05). Thus, this study supports the applying the PCB to patients with SIJP can be used as a helpful option to modify the activation patterns of the gluteus maximus and biceps femoris muscle.