Objective: To investigate the effects of 2, 2', 4, 4'-tetrabromodiphenyl ether ( BDE-47 ) on the differentiation of mouse embryonic fibroblasts-3T3-L1, so as to provide the basis for revealing the mechanism of environmental obesity factors. Methods: The 3T3-L1 cells were divided into five BDE-47 intervention groups ( 25, 18.75, 12.5, 7.5 and 2.5 µmol/L ), a positive control group (1 µmol/L 2, 4-thiazolidinedione) and a negative control group ( 0.1% dimethyl sulfoxide ) for the induction of differentiation. The lipid droplet accumulation in adipocytes was observed by oil red O staining treatment and detection of optical desity ( OD ) on the eighth day of differentiation. Triglyceride ( TG ) content was measured using the histiocyte TG enzymatic assay kit. The mRNA expression of adiponectin and peroxisome proliferator activated receptor-γ ( PPARγ ) was measured by RT-PCR. Results: The positive areas of oil red O staining, OD values, TG content and mRNA expression of adiponectin and PPARγ in 3T3-L1 cells were significantly different among seven groups ( P<0.05 ). The positive areas of oil red O staining and OD values in the BDE-47 groups with different concentrations were higher than those in the negative control group ( P<0.05 ). The 18.75 µmol/L BDE-47 group had higher TG levels than the negative control group ( P<0.05 ). The mRNA expression of PPARγ in the 25, 18.75, 12.5, and 7.5 µmol/L BDE-47 groups and the positive control group was higher than that in the negative control group ( P<0.05 ). The mRNA expression of PPARγ in the 12.5 µmol/L BDE-47 group was higher than that in the 25, 18.75, 7.5, 2.5 µmol/L BDE-47 group and the positive control group ( P<0.05 ). The mRNA expression of adiponectin in the 12.5, 7.5 µmol/L BDE-47 group and the positive control group was higher than that in the negative control group ( P<0.05 ). The mRNA expression of adiponectin in the 12.5 µmol/L BDE-47 group was higher than that in the 25, 18.75, 2.5 µmol/L BDE-47 group ( P<0.05 ). The mRNA expression of PPARγ and adiponectin in the different concentration groups of BDE-47 distributed like inverted "U" shape. Conclusion BDE-47 can promote the differentiation of 3T3-L1 preadipocytes. Low concentration of BDE-47 may induce adipocyte differentiation by activating PPARγ.