The invention discloses granules and a preparation method thereof. The granules comprise quantum dots; a surface ligand is combined with the surface of the quantum dot; the surface ligand is a substance with a structure shown in the specification. According to the invention, delocalized conjugated electron cloud is formed through an organic group with a conjugated system; a delocalized conjugatedelectron cloud system is pushed to a coordination group through an electron-donating organic group; therefore, the coordination capability of coordination lone pair electrons of coordination atoms onthe coordination group and the coordination atoms on the surface of the quantum dot is greatly enhanced, and the firmness of coordination bonds is enhanced, so that the sufficient passivation of the surface of the quantum dot can be effectively ensured, and the light emitting performance of a quantum dot material is improved.