To investigate the free fatty acid metabolic changes in animal model of femoral head necrosis，and identify the preventive effect of Chinese herbal compound to this disease.Methods:The free fatty acid contents in plasma and femoral head tissues of animal models were detected with high performance liquid chromatography (HPLC).Results:On the third and fifth week，the animal plasma and tissues of the femoral head appeared free fatty acid metabolism disorder.Conclusion:Abnormal metabolism of free fatty acid is an important pathological basis of femoral head necrosis; and traditional Chinese medicine can prevent early stage of femoral head necrosis.