Abstract: Various economics pig breeds show remarkable difference on their fat deposition ability. The objective of this study is to determine their genetic difference by determining their gene expression level during the fat deposition growth in Bamei pigs and Largewhite pigs. A total RNA was extracted from dorsal subcutaneous adipose tissue at 4 months old of Bamei and Largewhite pig breeds, respectively. The first-strand cDNA was synthesized by reverse transcriptase using random hexamer primer. A pair of primers were designed based on the sequence of rat Suppressor of Cytokine Signaling-3 gene (SOCS-3). The single tube Semi Quantitative Reverse TranscriptionPolymerase Chain Reaction (SQ RT-PCR) was applied to determine their expression level of SOCS-3 mRNA in adipose tissue between Bamei pig and Largewhite pig. The β-actin gene was selected as internal control. After amplication, agarose gel electrophoresis was performed and various expression bands and their Optical Density (OD) value were analyzed by Dolphin-DOC software. The result showed that the expression level of SOCS-3 mRNA in dorsal subcutaneous adipose tissue in Bamei pig was significantly higher than that of Largewhite pigs (P<0.01). This finding suggests that the difference of SOCS-3 gene expression level in adipose tissue may be one of the main reasons which result in the different fat deposition ability between different pig breeds.