Abstract: The preparation of poly(ethylene terephthalate)-poly(N-vinyl pyrrolidone)(PET-PNVP) composite films with higher hydrophilicity and biocompatibility was conducted by using the low temperature plasma treatment and UV-induced technique. The structure and morphology of PET-PNVP composite films were also characterized systematically through Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM). Effects of various parameters such as initiator concentration, UV irradiation time and monomer concentration on grafting degree were also analyzed comprehensively. The wettability results showed that the hydrophilicity of PET-PNVP composite films had been improved considerably. Vitro blood compatibility experiments exhibited better blood compatibility for PET-PNVP composite films. The cytotoxicity of PET film was also detected via MTT method and the results showed that PET-PNVP composite film was non-toxic for cell.