OBJECTIVE : The aim of this study was to retrospectively compare and evaluate the midterm curative effect of two different bone flap grafts in the treatment of early non-traumatic osteonecrosis of the femoral head (ONFH). METHODS : A total of 180 patients (199 hips) with early non-traumatic ONFH received surgical treatment by sartorius muscle-pedicle bone flap graft (SMBF) (104 patients, 64 males and 40 females; mean age 34.67 ± 3.24 years) or circumflex iliac deep bone flap graft (CIDBF) (76 patients, 44 males and 32 females; mean age: 35.54 ± 3.37 years) from July 2004 to July 2009. The comparison between the groups was made with Harris score before and after surgery, length of incision, operative time, amount of bleeding, postoperative X-ray. Association Research Circulation Osseous (ARCO) staging was performed. RESULTS : The preoperative Harris hip score of two groups were 68.26 ± 1.26 and 69.35 ± 1.31, respectively. Patients' ARCO staging indicated 36 hips of stage IIa, 115 hips of stage IIb and 48 hips of stage IIc. The etiology of ONFH mainly including hormones (93 patients), alcohol (64 patients) and other (23 patients). The mean follow-up time of SMBF and CIDBF groups were (51.78 ± 2.35) and (52.73 ± 3.71) months, respectively. The time of removing sutures, operation time, amount of bleeding and length of incision in SMBF group were superior to those in the CIDBF group, and those differences between the SMBF and CIDBF groups were not significant (all p values > 0.28). The Harris score between the two groups was similar after operation and postoperative 12 month, and the difference was not statistically significant (p > 0.05), whereas the difference of the postoperative 24 and 48 months was statistically significant (p ˂ 0.05). X-ray analysis showed improvement of osteonecrosis in both two groups after surgery, and as time went on, the total hip amount decreased, the replacement amount increased. CONCLUSIONS : Both bone flap grafts appear to be effective methods for treatment of early osteonecrosis of femoral head (ARCOⅡ), and the SMBF is a relatively simple technique and easy for mastering, and it is a reliable method for clinical application. METHODS : Level III, Therapeutic Study.