Abstract: Sulfide all-solid-state lithium metal batteries have received increasing attention due to their high specific energy density and excellent safety, but serious interfacial problems still limit their further development. In order to solve the difficulty that Li6PS5Cl solid-state electrolyte is unstable to metallic lithium, a composite interface layer of garnet oxide solid-state electrolyte (LLZTO) and Ag was used to improve the lithium anode interface of Li6PS5Cl all-solid-state battery. The effects of LLZTO-Ag composite interface layers with different combination manners, such as simply dispersed LLZTO - Ag composite, even dispersed and coated composite, and nanometer material ball-milled composite, on the anode interface of Li6PS5Cl all-solid-state lithium metal batteries were studied. The results show that the composite interface layer of LLZTO@Ag composite layer obtained by nano particle ball milling can effectively prevent lithium dendrite growth and battery short circuit. Under the optimal process, the first-cycle efficiency of the all-solid-state lithium metal battery at 0.1 C is 77.5%, the discharge specific capacity is 187.3 mAh g?1, and the capacity retention rate is 81.7% after 100 cycles at 0.3 C.