Lumbo-pelvic pain (LPP) is a common disorder in women after pregnancy due to ligament laxity and postural changes. Transverse abdominis (TrA) and pelvic floor muscle (PFM) activity is important for lumbo-pelvic stability. The purpose of this study was to compare the effect of stabilization exercise (SE) and general exercise (GE) on TrA and PFM muscle activity and pain intensity in women with postpartum LPP. A randomized controlled trial study was conducted on 68 women with postpartum LPP. Patients were randomly divided into two groups of stabilization exercise (SE) and general exercise (GE) and received either SE or GE exercise for 8weeks three times a week. Ultrasound imaging was utilized to measure the thickness change of TrA muscles during abdominal hollowing (AH) and bladder base displacement. These measurements were used as an indicator of TrA and PFM muscle activity. Pain intensity, thickness changes of the TrA muscle and bladder base displacement were measured pre- and post-intervention. The results showed that there was no significant difference in pain relief after intervention between groups. The differences in TrA and PFM activity between groups were significant (P < 0.05). PFM and TrA muscle activity was significantly increased after SE in women with postpartum LPP (P < 0.05). SE improved both PFM and TrA muscle function more than GE in women with postpartum LPP. However, the clinical outcome of pain relief was not greater in the SE group.