Objective To explore the probable mechanism of Huoxue Tongluo Decoction in treating steroidinduced avascular necrosis of femoral head. Methods Ninety-six Japanese big ear rabbits were randomly divided into prevention plus treatment group

treatment group

model group and blank group

with 24 in each. The steroidinduced avascular necrosis of femoral head model was established by gluteal intramuscular injection of prednisone acetate at a dose of 8 mg / kg. In the second week

the prevention plus treatment group was fed with Huoxue Tongluo Decoction diet

while the other groups were fed with normal diet

once a day

for a week. From the third week on

the prevention plus treatment group and the treatment group were fed with Huoxue Tongluo Decoction diet

while the model group and the blank group were fed with equivalent normal diet

once a day

for 6 weeks. The expression of alkaline phosphatase（ AKP）

osteocalcin（ BGP）

basic fibroblast growth factor（ b FGF）

transforming growth factorβ1（ TGF-β1）

bone morphogenetic protein 2（ BMP-2）

and platelet-derived growth factor B（ PDGF-B） was detected with immunohistochemical method. Results The levels of TGF-β1

b FGF

BGP

BMP-2 and PDGF-B were significantly lower

while the level of APK was significantly higher in model group compared with those in the blank group（ P < 0. 05 or P < 0. 01）. The levels of TGF-β1

b FGF

BGP

PDGF-B in prevention plus treatment group and treatment group were remarkably higher

while the APK was remarkably lower than those in the model group

and the level of BMP-2 in the prevention plus treatment group rose evidently（ P < 0. 05 or P < 0. 01）. Conclusion Huoxue Tongluo Decoction might promote the repair of osteonecrosis through up-regulating the expression of BGF

TGF-β1

b FGF and PDGF and down-regulating the expression of APK in bone tissue.