Objective:To study the effects of medicated serum of Pingmu Decoction on protein expressions of FAS,FAS L,CHOP and CASPASE-4 in orbital adipocytes in Graves’ ophthalmopathy,and discuss the mechanism of apoptosis in orbital mature adipocytes. MethodsThe orbital preadipocytes from patients with Graves’ ophthalmopathy were cultured in vitro,and differentiated into the mature adipocytes after cell passage and induction. The medicated serum of Pingmu Decoction were prepared,which divided into the low-,medium- and high-dose group with the final concentrations as 5%,10% and 20% respectively. The proliferation of preadipocytes was detected by MTT assay. The effects of medicated serum of Pingmu Decoction on protein expressions of FAS,FAS L,CHOP and CASPASE-4 in orbital mature adipocytes were detected by Western blotting.  Results:①The MTT assay showed that,compared with the blank control group,the growth curve was significantly downward in the Pingmu Decoction groups with low-,medium- and high-dose,and the decrease trend of activities in the medium-dose group was the most significant. There was no statistically significant difference between the dexamethasone group and blank control group(P>0.05). Compared with the blank control group at the same timepoint,the OD value was decreased in the Pingmu Decoction groups with low-,medium- and high-dose,and the decrease in the medium-dose group was the most significant with statistical difference(P<0.05). ②The results of Western blotting showed that,except the dexamethasone group,compared with the blank control group,the protein expressions of FAS and FAS L were up-regulated in the Pingmu Decoction groups with different doses,with statistical differences(P<0.05). The protein expression of FAS was highest in the medium-dose group,followed by low-dose group；the protein expression of FAS L was highest in the high-dose group,followed by medium-dose group,but there was no statistically significant difference between these two groups. Except the dexamethasone group,compared with the blank control group,the protein expressions of CHOP and CASPASE-4 were up-regulated in the Pingmu Decoction groups with different doses,with statistical differences(P<0.05).The protein expression of CHOP was highest in the high-dose group,followed by medium-dose group；the protein expression of CASPASE-4 was highest in the medium-dose group,followed by low-dose group.  Conclusion:Pingmu Decoction can induce the activation of FAS,FAS L,CHOP and CASPASE-4 through death receptor and endoplasmic reticulum pathway,promote the apoptosis of mature adipocytes,and then reduce the accumulation of orbital adipocytes,which plays the therapeutic role.