Polyethylene oxide(PEO) based solid-state batteries have high safety and high energy density, making them suitable for next-generation energy storage devices. However, their energy density reaches a limitation due to the narrow electrochemical window of PEO solid electrolyte. The electrode materials that are compatible with PEO electrolyte is less, thus handering it from being put into wide application. At the PEO/electrode interface, there are side reactions between anode/PEO and PEO cathode. Some strategies are proposed to reduce the side reactions, electrochemical performances of solid-state batteries are improved. To understand the change of interface, several advanced characterizations are employed, which can offer scientific evidence of increasing the interface stability in the future.