The present disclosure relates to a method for preparing a silicate phosphor and the silicate phosphor. The method includes (1) a hydrothermal treatment step of obtaining a layered silicate substituted with a rare-earth metal by hydrothermally treating an aqueous solution as a reaction solution, the solution containing rare-earth metal ions, NaOH and silica, and (2) a calcinating step of forming a crystalline silicate by calcinating the layered silicate substituted with the rare-earth metal. According to the method for preparing the silicate phosphor, the silicate phosphors, which can be used as phosphors for LEDs in the aspects of high covalent character, high luminescent intensity and stability at high temperature, may be prepared by a simplified, economic process. Also, the silicate phosphors may selectively emit red, green or blue light by virtue of the substitution of a silicon position with rare-earth metals of various types.