A sintering-free inorganic ceramic brick-plate and its preparation method are disclosed. The sintering-free inorganic ceramic brick-plate includes following components by mass parts: 25-40 parts of magnesium oxide; 20-35 parts of magnesium chloride; 20-30 parts of fumed silica; 10-20 parts straw powders; 0.1-0.3 parts of graphene powders with a particle size of 2000 meshes; and 0.2-0.4 parts of airgel powders with a particle size of 100 nm. Compared with the prior art, the present invention utilizes a variety of raw natural non-toxic natural mineral raw materials, namely, the graphene powders with the particle size of 2000 meshes and the airgel powders with the particle size of 100 nm for mixing, and then the mixed raw materials can be solidified at room temperature and form sheets, and then the surface of the sheets is processed through printing or spraying glaze, so as to achieve the effect of high-grade tiles and natural marble.