Abstract: An increasing number of non-viral vectors are being developed for the use of gene delivery nowadays. As a kind of versatile vector, poly(ethylene-imine) (PEI)-based cationic polymers receives intensive attention. Most of these research efforts are focused on its non-biodegradablity and cytotoxicity while several strategies have been explored to enhance the gene transfection efficiency of PEI-based derivatives. In this review, some of the recent development of PEI-based gene delivery vector, including synthesis of novel PEI-based vectors, construction of new PEI-based transfection system in vitro as well as in vivo applications were summarized.