The invention relates to the field of rock plate glaze decoration, and discloses a fast-fired colorful pearlescent glaze, a rock plate and a preparation method of the rock plate. The fast-fired colorful pearlescent glaze comprises pearlescent glaze and pearlescent ground glaze, wherein the pearlescent glaze comprises perlite, boric acid, strontium carbonate, zirconium oxide, chalk soil, zirconite, high-boron frit, lithium fluoride, cerium oxide and corundum; and the pearlescent ground glaze comprises potassium feldspar, albite, quartz powder, nepheline, barium carbonate, aluminum oxide, dolomite, calcined talc and zirconium silicate. The pearlescent glaze disclosed by the invention has relatively strong adhesive force and good glossiness, a ceramic product is endowed with an excellent seven-color pearlescent visual effect, and the product can display color effects of different degrees under light rays of different angles and is similar to a color layer in a shell; and meanwhile, the product is suitable for sintering in a roller kiln at the temperature of 1150-1200 DEG C, and rapid sintering is realized.