Purpose : The purpose of this study was to investigate the change of abdominal muscle activation during unilateral leg raising in supine position among three hip abduction angles($0^{circ}$, $15^{circ}$, $30^{circ}$). Methods : Twenty eight able-body volunteers who had no medical history of low back and hip joint were recruited for this study. Abdominal muscle activity was recorded using surface EMG from both sides of the rectus abdominis, internal/external oblique muscle during leg raising in each position. Results : The muscle activations induced under the three different positions were compared and results showed that there was significant difference only in the right external oblique muscle activation. Conclusion : This study suggest that leg raising of different hip abduction angles without trunk control has little influence on abdominal muscle co-activation.