A manufacturing method of a lithium metal cathode with a solid-liquid composite interface layer belongs to the secondary cell technology field. The method comprises the following steps of firstly, stacking a lithium band and an interface layer, and then rolling through a rolling mill so that the interface layer is attached to the surface of the lithium band; and then, wetting the interface layer on the surface of the lithium band with an ether electrolyte so as to acquire the lithium metal cathode with the solid-liquid composite interface layer. The interface layer is made of one or more of anon-woven fabric, carbon cloth, carbon paper, a glass fiber, and a nano carbon layer. The ether electrolyte consists of a solvent and lithium salt. Through the absorption effect of a multi-interface layer to the ether electrolyte, a solid-liquid composite protective layer is formed on the surface of lithium metal. The solid-liquid composite protective layer can increase the cycle life of the lithium metal cathode in an ester electrolyte by 50%. .