The invention relates to a lithium aluminate solid-state ion conduction layer, a preparation method thereof and an all-solid-state electrochromic device comprising the solid-state ion conduction layer. The chemical composition of the solid-state ion conduction layer is LiAlOx, wherein x is 1-5, preferably, 1.5-2. The solid-state ion conduction layer of the invention is low in price and easy to obtain and can be used for conducting lithium ions between a first color-changing layer and a second color-changing layer of the electrochromic device to realize electrochromism and improving the ion conductivity and the ion conduction rate.