The invention discloses a luminescent ion Dy<3+>-doped yttrium potassium pyrophosphate luminescent crystal material, and a preparation method thereof. The main chemical composition of the luminescention Dy<3+>-doped yttrium potassium pyrophosphate luminescent crystal material is K5Y(1-x)P4O14:xDy, wherein x = 0.02-0.12. The preparation method comprises the following steps: (1) preparation and crystal structure detection of a matrix material K5YP4O14 single crystal, wherein the crystal is synthesized by a high temperature solution process, structure analysis determines that the chemical formula of the crystal is K5YP4O14, the crystal structure belongs to a triclinic system, the space group is P-1, and unit cell parameters are as follows: a = 0.742 nm, b = 1.141 nm, c = 1.760 nm, alpha = 92.046 DEG, beta = 98.582 DEG, gamma = 92.012 DEG, Z = 4, and V = 1.470 nm<3>; and (2) preparation of Dy<3+>-doped yttrium potassium pyrophosphate phosphor, wherein the phosphor is synthesized by a hightemperature solid phase technology, the synthesized phosphor emits yellow fluorescence under the excitation of 349 nm lights, and can be applied to the fields of luminescence, display and illumination as yellow phosphor. The preparation method has the advantages of simple process steps, stable and reliable process conditions, and cheap and easily available raw materials.