Objective Analysis of the effect and the mechanism of adenovirus with down regulation of matrix metalloproteinase inhibitor 1 (TIMP-1) achieved targeting by ultrasound microbubbles combined with ultrasound irradiation for liver fibrosis in rats. Methods Recombinant adenovirus-mediated with down regulation of TIMP-1 gene was constructed and a mixture of recombinant adenovirus and ultrasound contrast agent was prepared.The rat liver fibrosis model was established and divided into 5 groups : model group; adenovirus group (recombinant adenovirus); adenovirus microbubble group (mixture of recombinant adenovirus and ultrasound contrast agent); experimental group (ultrasound irradiation + mixture of recombinant adenovirus and ultrasound contrast agent); ultrasound adenovirus group (ultrasound irradiation + recombinant adenovirus). The rats were sacrificed after 24 hours and liver sections were prepared. The expression of EGFP in each group was observed and the transfection rate was analyzed. The liver slices were stained by Masson to judge the stage of liver fibrosis. ANOVA analysis was used to compare the levels of alanine aminotransferase (ALT) , aspartate aminotransferase (AST) , bydroxyproline (Hyp) , hyaluronic acid (HA) , type IV collagen (CIV) and laminin (LN) in each group. The relative expression levels of TIMP-1 and matrix metalloproteinase 13 (MMP-13) in each group were detected by Western blot. Results The transfection rate of the experimental group was higher than that of the adenovirus group (q = 3.418) , the adenovirus microbubble group (q = 3.756) and the ultrasonic adenovirus group (q = 5.502) , and the difference was statistically significant (P < 0.05); Pathological examination showed that the degree of fibrosis in the experimental group and the grade of liver fibrosis were lower than the other groups (P < 0.01). The activities of ALT, AST, HA, LN, CIV and Hyp in the experimental group were lower than those in the other 4 groups.Western blot showed that the level of TIMP-1 protein expression was highest while the level of MMP-13 protein expression was lowest in the experimental group than those in the other groups. Conclusion Adenovirus with down regulation of TIMP-1 achieved targeting by ultrasound microbubbles combined with ultrasound irradiation can inhibit the activity of TIMP-1 and improve the degree of liver fibrosis. Gene therapy is an potential therapeutic method in the application of treating liver fibrosis.