Abstract: Objective To investigate the effect of heparanase expression reduction on biological behavior of colon cancer cell lines. Methods Heparanase expression levels of four colon cancer cell lines（SW620，SW480，LoVo and CACO-2）were measured by real-time PCR. Three heparanase-specific small interfering RNA（siRNA1，siRNA2 and siRNA3）were designed，synthesized and transfected into the cell line with the highest expression of heparanase among the 4 colon cancer cell lines. The heparanase expression was measured by real-time quantitative PCR and Western blotting. Cell proliferation was detected by MTT colorimetry. The in vitro cell invasion was detected by transwell chamber method. Results The expression of heparanase in SW480 cell line was higher than the other 3 cell lines. Transfection of the 3 specific siRNAs could reduce the expression of heparanase at protein and mRNA levels，especially siRNA3 in a dose-dependent manner. The siRNA3mediated silence of heparanase suppressed the proliferation of SW480 cells，and the in vitro invasion of SW480 cells was attenuated in a dose-dependent manner. Conclusion Gene silence of heparanase can efficiently abolish the malignant biological behavior of colon cancer cell lines in vitro， suggesting that heparanase could be regarded as a novel target for gene therapy of colon cancer.