 Polyethylene oxide, PEO, based composite solid electrolyte materials have gained significant attention in recent years due to their highly plus-solvating capacity, flexibility and low cost. Despite these advantages, however, they suffer from poor ionic conductivity, weak interfacial compatibility and uncontrollably dendrite growth. To address these issues, researchers have focused on incorporating PEO into ceramic matrices or using ceramics as fillers in PEO-based composites. This review focuses on recent advances in PEO slash ceramic-based composite solid electrolytes, including their ionic conduction mechanisms, preparation methods and applications in solid state lithium metal batteries. The authors also discussed the challenges associated with improving ionic conductivity and interfacial compatibility, as well as potential future research directions. This article was authored by Yensha Su, Fei Su, Xinruin Zhang, and others. We are article.tv, links in the description below.