Abstract: At present, lithium-ion batteries face many problems due to the use of liquid electrolytes, such as narrow operating temperature range, poor thermal stability, easy leakage, and formation of lithium dendrites. The development of all-solid-state lithium batteries is one of the feasible ways to improve the energy density and safety of batteries. In this paper, the types and conduction mechanisms of solid electrolytes are firstly summarized, and then the selection of polymer matrix and lithium salt in organic-inorganic composite solid electrolytes and the effects of inorganic fillers of different dimensions on electrolyte properties, especially mechanical properties, are described in detail. Finally, the research summary and prospect of organic-inorganic composite solid electrolytes are presented.