The present invention discloses a drug carrier with the capability of systemic administration through intravenous injection, its preparation methods and it is used for tumor gene therapy, it is belong to the field of tumor-targeted therapy. The carrier of the present invention is a novel liposome which is composed of DOTAP or its analogue and lecithin or its derivative in molar ratio of 20:(7-13), it can form stable complex with bioactive materials, and can deliver these bioactive material to the targeted cells cultured in vitro or in vivo. The complex of the present invention has a larger packaging capability, and the particle size is greatly reduced, that is optimized to 200 nm and below, in an environment of high serum concentration, it maintains high transfection efficiency. The carrier of the present invention packages DNA of tumor suppressor genes or cell suicide gene by forming complexes which can be specifically delivered into tumor cells in vitro, ex vivo or in vivo for gene therapeutic purposes.
