The polyethylene (PE)-supported polymer membranes based on the blended polyvinylidene fluoride (PVDF) and cellulose acetate butyrate (CAB) are prepared for gel polymer electrolyte (GPE) of lithium ion battery. The performances of the prepared membranes and the resulting GPEs are investigated by scanning electron microscopy, electrochemical impedance spectroscopy, linear potential sweep, and charge–discharge test. The effect of the ratio of PVDF to CAB on the performance of the prepared membranes is considered. It is found that the GPE based on the blended polymer with PVDF:CAB=2:1 (in weight) has the largest ionic conductivity (2.48×10−3 Scm−1) and shows good compatibility with anode and cathode of lithium ion battery. The LiCoO2/graphite battery using this GPE exhibits superior cyclic stability at room temperature, storage performance at elevated temperature, and rate performance.