Abstract: To investigate the molecules responsible for the invasion potential of HCC by focusing on matrix metalloproteinase (MMP) in particular, MMP-9 and the corresponding tissue inhibitor of metalloproteinase (TIMP-1) .Semi-quantitative Reverse transcription polymerase chain reaction (sRT-PCR) was used to examine the expression of MMP-9 and TIMP-1 mRNA in twenty pairs surgical specimens of HCC and adjacent non-tumoral liver which were obtained from patients undergoing surgical resection.The correlation between expression of MMP-9 and TIMP-1 mRNA and clinic opatholigical features was observed.The levels of MMP-9 mRNA and TIMP mRNA in the tumorous tissues were significantly higher than those in the nontumorous tissues (P<0.01, P<0.05) .It was found that the expression of MMP-9 mRNA in HCC with capsular infiltration was significantly higher than in HCC without capsular infiltration.The result here indicated the correlation between expression of MMP-9 and TIMP-1 mRNA and the important histopathological characteristics regarding invasion and metastasis.The levels of MMP-9 mRNA in HCC suggests MMP-9 closely participates in capsular infiltration.