||Obesity is becoming a very important issue in the developed countries. The incidence of obesity was due to the excessive proliferation and differentiation of adipocytes. 3T3-L1 was the precursor cell lines and most commonly used to assess the differentiation, gene expression and insulin resistance. First we study tried to establish a 3T3-L1 preadipocyte culture and differentiation system, and the 3T3-L1 was used to screening the anti-obesity and ani-ROS forming compounds from the fermentation broth of sake-lees fermented with five lactic acid bacteria (Lb. casei E7, Lb. casei E15, Lb. casei E30, Lb. plantarum E51, Lb. acidophilus V12). The results indicated that two groups of fermentation broth (LFSE7-48h and LFSE15-48h) showed the highest inhibition activity. Partially purified fermentation broth confirmed that the anti-adipogenesis activity was found in the lower molecular weight fraction (LFSE7, located between 3-10 kDa and LFSE15, less than 3 kDa) . Furthermore, we also evaluated the effects of these on the expression of C/EBPβ, SREBP-1, PPARγ and C/EBPα, which are transcriptional factors essential for adipocytes differentiation and lipogenesis, using the RT-PCR technique. Results showed that LFSE7-48hr and LFSE15-48hr at concentrations above 10 mg/ml significantly decreased the mRNA expression of C/EBPβ, C/EBPα, PPARγ and SREBP-1 by12.3 %, 5.5 %, 0.67 % and 11.4 %；23.6 %, 8.9 %, 7.8 % and 4.8 %. So the LFS may be inhibit C/EBP β expression, and indirect effect other transcriptional factors. In the anti-ROS forming activity assay, LFSE7-48hr and LFSE15-48hr have strong activity, the cytokines and inflammatory factor (TNFα, IL-6, MCP-1) has dose-dependent relationship, and to promote the adiponectin.