A novel thermo-sensitive switching membrane has been prepared by radiation-induced simultaneous grafting N-isopropylacrylamide (NIPAAm) onto chitosan membrane. Fourier transform infrared spectroscopy (FTIR) was used to identify the structure of the grafted membranes. The surface morphology of the grafted membrane was observed from scanning electron microscopy (SEM). Pure water flux measurements showed that water flux of the grafted membrane decreased with the increase of temperature, while that of chitosan membrane was constant. It was proved that grafted membrane was sensitive to temperature.