Abstract: The alkaline composite polymer solid electrolyte with good properties was prepared by the solution cast method with poly vinyl alcohol (PVA)，carboxyl methyl cellulose( CMC) and KOH as raw materials. An optimized component ratio of m(PVA)∶m(CMC)∶m(KOH)=3∶1∶6 was obtained by investigating the relationship among the water capacity，conductivity and component of the solid electrolyte. The thermal stability and electrochemical stability of the electrolyte was investigated by DTA and CV techniques. The sample lost free water at 66℃ and hydroxyl bond water at 90℃，hydroxyl condensation occurring at 350℃ showed chemical dehydration of the inner molecule. A secondary nickel-zinc battery with the alkaline solid electrolyte was fabricated，a charge voltage plateau of 1.93～1.95Ｖand a discharge voltage plateau of 1.78～1.45V were observed respectively in the charge and discharge process of the battery at variable currents of 2～10 mA/cm2. The battery was charged and discharged at 5 mA/cm2 for 10 cycles. A coulomb efficiency of 92% was obtained at the last cycle，which showed that the prepared electrolyte had good properties.