Two kinds of monomer (SSS and VBTAC) containing ion-exchange groups were cografted with HEMA onto HDPE membrane respectively by pre-irradiation grafting. Thus we obtained ion-exchange membranes with anti-bacteria function. The grafted membranes had good hydrophilicity compared with the hydrophobicity of the base film. The research was focus on 3-point: (1) Study the process of the grafting reaction, structure of the grafted membranes, chemical and physical properties of the grafted membranes. (2) Quantitative study of the hydrophilicity of the grafted membranes, evaluate the hydration number and surface free energy of the membranes. (3) Study the antibacterial activity of the grafted membranes. The antibacterial ability of the VBTAC membrane was so good that it would be fit for an antibacterial material.