The invention belongs to the field of refractory material, and relates to an 800kg-class energy-saving heat insulation lining material and a preparation method thereof which are widely applied to various heat engineering kiln industries. The lining material is prepared by adding water reducing agent and dispersing agent into the mixture of ceramsite with different grain size distribution, expanded perlite, Guangxi mud and pure calcium aluminate cement. Compared with the common light heat insulation lining material, the energy-saving lining material prepared by the invention has the characteristics of high strength, low heat conduction rate, good heat insulation effect and long service cycle; furthermore, the energy-saving heat insulation lining material has the volume density of 800 plus or minus 30kg/m<3> at the normal temperature, and has important significance for energy conservation and emission reduction as well as reducing the running cost of heat engineering kilns.