Abstract: An asymmetric sodium-based solid-state composite electrolyte includes a first solid-state composite electrolyte layer and a second composite electrolyte layer obtained by laminated coating method. Both the two solid-state composite electrolyte layers include a polymer matrix, an inorganic filler, a sodium salt and a plasticizer, the difference is the electron conductive agent added with the mass ratio ranges from 1 wt. %˜10 wt. % into the second solid-state composite electrolyte layer. In a battery assembled with the asymmetric sodium-based solid-state composite electrolyte, the first solid-state composite electrolyte layer is contiguous with a positive electrode, and the second solid-state composite electrolyte layer is disposed between the first solid-state composite electrolyte layer and a negative electrode.