Solid electrolyte of lithium battery and all-solid-state lithium battery

The invention discloses a solid electrolyte of a lithium battery and an all-solid-state lithium battery. The solid electrolyte is composed of a cross-linked polymer and a lithium salt; the cross-linked polymer is prepared from a silane coupling agent and polyethylene glycol by use of cross-linking reaction; the solid-electrolyte is good in heat resistance, good in processability and relatively high in electrical conductivity; a prepared electrolyte film is good in mechanical properties and high in electrical conductivity, and can be used for preparing a safe all-solid-state lithium battery capable of keeping good electrochemical stability at high temperature.