Abstract： Objective To investigate the oncolytic effect of E1B mutant adenovirus (d11520) on human malignant gliomas. Methods Ad-βgal vector was used to investigate the infectibility of dl1520.U251,Hep3B (positive control) and T24 (negative control) cell lines were infected with dl1520respectively at 50,5,0.5,0.005 and 0 pfu of multiplicity of infection (MOI).The replication efficiency of d11520 in host cells was assessed by plaque assay.The cytopathic effect (CPE) was assessed by crystal violet staining in a panel of tumor cells. Results Crystal violet staining showed the Hep3B cell line was the most sensitive to dl1520 and had the fastest CPE,followed by the U251 cell line,while the T24cell line had no CEP.The replication and infection rates ofdl1520 in the U251 cell line were lower than in the Hep3B cell line but significantly higher than in the T24 cell line (P＜0.05). Conclusion The E1B mutant adenovirus (dl1520) has a significant oncolytic effect on human malignant gliomas.