BACKGROUND:: Alcohol has become pathogenic factors of avascular necrosis, and the alcohol induced abnormal lipid metabolism in bone marrow may be the important reason for the onset of avascular necrosis, but the mechanism is not clear yet. OBJECTIVE:: To observe the changes of structure and function of fat cells under the action of alcohol, in order to analyze the pathogenesis of alcoholic femoral head necrosis. METHODS:: Primary adipocytes in vitro culture technique was used to obtain rabbit femoral head intramedullary adipose tissue, and then the fat cells were separated, and the phenotype was identified with oil red O staining. The passaged stable intramedullary fat cells were collected. Coverslip was cut into 1 cm × 1 cm in size, and placed in the 24-well culture plate before planting. The cells were randomly divided into alcohol group and control group, 24 holes (each hole for a sample) in each group. The control group was without alcohol, while the alcohol group was added with 0.15 mol/L alcohol. At 4, 6, 8 and 10 days, the culture medium was replaced. Medium was changed and no longer adding alcohol, and then cultured for 10 days. When the culture terminated, the coverslip was removed for oil red O staining. Finally, the morphology and the number of the fat cells were observed under light microscope. RESUTLS AND CONCLUSION:: With time prolonging, the number of fat cells in the alcohol group was significantly more than that in the control group (P < 0.001). The lipid droplets in the two groups were gradually increased and enlarged, but more significant in the alcohol group. The number of intramedullary fat cells in the alcohol group after cultured for 4, 6, 8 and 10 days was respectively (200.90±24.60), (1 102.30±76.73), (1 160.30±28.37) and (1 199.70±44.74)/cm; the number of intramedullary fat cells in the control group was respectively (99.80±10.82), (0.40±94.71), (1 000.20± 41.85) and (1 059.80±26.79)/cm, the number of fat cells increased with the time of alcohol influence. Alcohol can promote the intramedullary fat cells to increase and enlarge, and this may be the main reason for femoral head necrosis, as long-term alcoholism can lead to bone marrow fat tissue increasing, intraosseous pressure increasing and perfusion reducing, thus resulting ischemia.