Abstract: Objective To analyze the protein changes of adipocyte differentiation using proteomic technique in order to explore the mechanism of adipogenesis.Methods The model of adipocyte differentiation of mesenchymal stem cells(MSCs) was used for identifying the changes of proteins following the differentiation in vit ro.Protein lysates obtained from differentiated cells were compared after adipocyte differentiation for 0,1 and 3 weeks by 2-dimensional gel electrophoresis and tandem mass spectroscopy.Results 44 proteins were up or down2regulated over 2-fold in the process of adipocyte differentiation.The majority of the modulated proteins belonged to the following functional categories:metabolic(39%),cytoskeleton(11%),redox(6.8%),protein synthesis and degradation(15.9%),signal transduction(6.8%)and molecular chaperones(4.5%).Conclusion The modulated proteins play important roles in adipogenesis and MSCs are promising tools to investigate the commitment of multipotent precursor cells into individual cell lineages including preadiopcytes.