Abstract: Montmorillonite was modified，and organo montmorillonite/poly(vinylidene) fluoride hexafluoropropylene composed polymer electrolyte was prepared. Its morphologies and properties were characterized by scanning electron micrograph and XRD. The electrochemical properties of polymer batteries were studied with the AC impedance and charging-discharging test. The results show that the composed polymer membrane has rich micro-pores and exhibits 1.51 mS/cm of ionic conductivity at room temperature，and its electrochemical stability window reaches 5.5 V. When discharging at 0.1 current rate，the capacity maintenance ratio of the polymer battery prepared by LiCoO₂ cathode material is 95.3% after 50 cycles，and the polymer battery has excellent rate performance. By adding OMMT into polymer electrolyte，the interfacial impedance of polymer battery is stable，and its cycling performance is improved.