The widely use of volatile and flammable traditional organic carbonate-based electrolytes in high-performance lithium-ion batteries (LIBs) is prone to cause safety hazards. Solid-state polymer electrolytes (SPE) have been developed to address the safety issues due to their numerous advantages, such as solvent-free, low flammability, wide electrochemical stability window, and good thermal and mechanical stability. However, the polymer tends to recrystallize at room temperature leading to insufficient ionic conductivity. Organic-matter-based fillers (e.g., metal-organic frameworks, covalent−organic frameworks, and lithiophilic polymers) have been found to increase the ionic conductivity of SPEs effectively by decreasing the crystallinity of polymer, synchronously to improve the mechanical property, thermal stability, and interfacial compatibility. Porous zeolitic imidazolate framework-8 (ZIF-8) has been used as fillers in this study. The ZIF-8 are integrated with the PEGDA matrix in this study, showing enhanced electrochemical and mechanical properties. Such performance enhancement is due to the composite solid-state electrolyte inherited the advantages of both polymer and fillers. The fillers not only inhibited the recrystallization of the polymer but also prevent the dendrite growth of the Li. The polymeric PEGDA enhanced the contact interface between the electrolyte and electrodes. Therefore, PEGDA-based SPEs with ZIF-8 is of great promise for all-solid-state lithium metal batteries.