Abstract: Objective: To study the effect of somatostatin analogue octreotide on the expression of heparanase (Hpa) in the SGC-7901 human gastric cancer cells and to investigate its mechanism of action. Methods: The SGC-7901 human gastric cancer cells in logarithmic growth period were made into single cell suspension, and then co-cultured with different concentrations of Octreotide for 24 and 48 hours. The expression of Hpa was detected by semi-quantitative RT-PCR and immunocyto- chemical method. Results: a) After gastric cancer cells and octreotide of 1×10^-5mol/L and 1×10^-6mol/L co-cultured for 24 hours, the expression of HpamRNA was significantly decreased compared to the control group (P=0.000 and 0.001). After gastric cancer cells and octreotide of 1×10^-5mol/L and 1×10^-6mol/L were co-cultured for 48 h, the expression of Hpam RNA was significantly lower than that of the control group (P=0.000 and 0.000). At the concentration of 1×10^-5mol/L and 1×10^-6mol/L of octreotide, the expression of HpamRNA of co-culturing for 48 hours was lower than co-culturing for 24 h (P=0.002 and 0.003). There was no significantly difference between the octreotide 1×10^-5mol/L group, 1×10^-6 mol/L group and the controls (P>0.05). b) After gastric cancer cells and octreotide of 1×10^-5mol/L and 1×10^-6mol/L were co-cultured for 24 hours and 48 hours, the expression of Hpa protein decreased accordingly. Conclusion: Octreotide of 1×10^-5mol/L and 1×10^-6mol/L can significantly inhibit the expression of Hpa in SGC-7901 human gastric cancer cells, and may inhibit the invasion and metastasis of the tumors.