In order to investigate the ability of PEG-PEI copolymers as gene carriers for delivery of VEGF165. A series of PEG-PEI copolymers with different PEG grafting was prepared and the cytotoxicity was evaluated. Simultaneously，the VEGF165 gene segment with HindⅢ and BamHⅠ site was obtained by PCR, which was cloned into pEGFP-C1. PEG-PEI/ pEGFP-VEGF165 complexes were formed by self-assembly and transfected HUVEc. Transfection efficiency was evaluated by measuring the percentage of cells expressing green fluorecensce protein. The VEGF expression was detected by ELISA, RT-PCR, and the effect of transfection on growth of endothelial cell was evaluated by MTT. The results suggested that the formation of PEG-PEI copolymers could help to reduce the cytotoxicity of PEI. After transfection, the strong expression of green fluorescence protein was observed by fluorescence microscopy. The transfection efficiency was influenced by the number of PEG side chains and N/P ratio. Of all copolymers tested, the transfection efficiency of PEG-PEI(5-25-1) at N/P = 30 reached a maximum, which was much higher than that of PEI. The expression of VEGF protein and mRNA increased significantly, and HUVEc proliferation was accelerated after transfection.These results indicates PEG-PEI copolymers can be used as effective gene carriers for delivery of pEGFP-VEGF165 gene.