Abstract: Objective To investigate the inhibitory effect of endostar on human lung squamous cell carcinoma cell line H-520 and to reveal the possible mechanism of the inhibition. Methods The effect of endostar with various concentrations on the proliferation of H-520 cell was studied by MTT assay. Hoechest33258 staining was used for morphological examination and flow cytometry was used to detect the apoptosis and cell cycle distribution. Wound healing assay was used to evaluate the migration of H-520 cell after administration of endostar. Results Endostar inhibited H-520 cell proliferation with time-dose dependent style and induced cell apoptosis,the apoptosis rate was increased with the raise of endostar concentration(P<0.01).Flow cytometric analysis showed that cell cycle distribution changed and G₀/G₁ arrest occurred after exposure to endostar. Wound healing assay indicated that cells after administration of endostar were far less motile than control groups. The wound healing ratio after 24h between the endostar exposure and controls was significantly different. Conclusion Endostar inhibits proliferation of H-520 cells by inducing apoptosis,changing the cell cycle distribution and attenuating cell migration.