This paper reports the surface modification of different discharge gases (Ar, O-2, and Ar + O-2) plasma-treated polystyrene (PS) film by Ar plasma induced graft polymerization, with biocompatible monomer N-vinyl-2-pyrrolidone (NVP) is carried out to improve biocompatibility. The films are characterized by attenuated total reflectance Fourier transfer infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Water contact angle measurement demonstrates the modified films possess a relatively hydrophilic surface. Furthermore, the films are also examined cell attachment and proliferation in vitro using mouse fibroblasts (L929 cells). The modified film surface shows a better cell distribution and growth than that of the pristine PS surface. From cell culture experiments, it is also observed that Ar + O-2 plasma is more capable of increasing cell adhesion and proliferation. This method will provide a potential and effective solution for grafting useful component in future tissue-engineering applications. (C) 2012 Elsevier B.V. All rights reserved.