Recently, rechargeable lithium metal polymer battery (LMPB) attracts increasing attention because of its high safety and energy density properties. However, the high contact interfacial resistance of solid-state electrode and electrolyte is still an obstacle to satisfy the demand of high current density and long cycle stability, especially at room and lower temperature. Here, we develop a simple and efficient heat treatment method, to improve the interfacial compatibility between electrode and electrolyte in all-solid-state LMPB, successfully realizing workable LMPB at a reduced temperature (30 °C). The LMPB shows excellent cycling performance and rate capability in the voltage range of 2.5–4.2 V. The behavior of Li+ plating/stripping on the surface of lithium metal anode is greatly enhanced. Meanwhile, the interfacial resistance of the LMPB decrease significantly after the heat treatment process.