Abstract: In order to achieve tissue-specific siRNA therapy，the liver-specific siRNA in vivo expression plasmid had been investigated. It could be used for liver-specific hepatitis B treatment，overcoming a barrier about the siRNA in the clinical application. We used anti-EGFP siRNA instead of the anti-HBV siRNA in this study. The vector was expressed specifically in hepatocyte through construction can express siRNA. The constructed vector had been transiently transfected HepG2，MDA-MB-231，MDA-MB-293 cells respectively. Then the inhibition of siEGFP in the different cell lines had been evaluated and compared by Western blotting ananlysis. siEGFP was proved by Western blotting result to be more efficient to inhibit in the hepatic tissue origin clone HepG2 than other two groups. Tissue specificity was achieved through constructed carrier expressing siRNA specifically in hepatoma cell line，but not in other tissue cell. If we replaced the siEGFP with anti-HBV siRNA in this modified plasmid，it was highly possible to develop a liver-specifically expressing anti-HBV siRNA therapy.

Key words: RNAi; tissue-specific siRNA; liver-specific; EGFP; Western blotting