Abstract: A successful gene therapy largely depends on the development of effective,secure and targeting delivery vectors.Compared to the viral vectors,the non-viral vectors have many advantages including lower cytotoxicity,the potential to be administered repeatedly with minimal host immune response,targetability,stability in storage and ease to produce in large quantities.Especially,cationic polymers were given greatly concern.The latest advances on the modification of the polymers to reduce the cytotoxicity,improve the stability and transfection efficiency of the complex,and achieve targeting delivery,are reviewed in this paper.