Abstract: Genome RNA was extracted from adipose of pig and fatty acid synthase (FAS) gene mRNA was amplified using RT-PCR.A DNA fragment about 206 bp in length was obtained and the PCR product was cloned into pGEM-T vector. The FAS gene was isolated and sequenced from the positive clones screened. Sequenced analysis suggested that this fragment was partial sequence of FAS cDNA. The gene homology of fragment obtained in this study compared with that of reported FAS cDNA（AY183428）in adipocytes of porcine was 100%. Based on the FAS gene clone, an optimal semi-quantitative RT-PCR method was successfully constructed. Using 18S rRNA as inner control, the developmental gene expression of FAS in abdominal adipose was studied. The results showed that FAS gene expression in abdominal adipose is increased from 1 day to 28 weeks, the difference between 1 day and 28 weeks is significant (P<0.05).