The invention discloses silicate-based multi-color long-afterglow luminescent materials and a preparation method thereof. The silicate-based multi-color long-afterglow luminescent materials have the chemical structural expression of Ca3-x-ySiO7:xCe<3+>,yM, wherein x is the doping amount of Ce<3+>, y is the doping amount of M, M is Tb<3+> or Mn<2+>, 0<x<=0.1, and 0<=y<=0.3; H3BO3 with the mass fraction of 5-10% is used as a fluxing agent. The preparation method comprises the steps: synthesizing by adopting a high temperature solid state method in a reducing atmosphere; accurately weighing the raw materials according to the stoichiometric ratio, then mixing and grinding evenly, pre-sintering in air, then grinding again, calcining under a high-temperature reducing atmosphere, and when naturally cooling to the room temperature, grinding to obtain the multi-color long-afterglow luminescent materials. Different samples are excited by ultraviolet light, and the samples emit bright afterglow with different colors. The silicate-based multi-color long-afterglow luminescent materials have the advantages that the silicate-based multi-color long-afterglow luminescent materials have the advantages of no radioactivity, high brightness, good stability, and longer afterglow time; multi-color long afterglow is achieved in a single matrix, the raw materials are cheap and easy to get, and the preparation method is simple and practicable and is suitable for large-scale production.