The invention belongs to the technical field of nanometer materials, and relates to a preparing method of a fluorescence silk fabric. Through adjusting growing morphology and thickness of rare earth metal organic frame materials (MOFs) on the fabric, intelligent color regulation and control can be achieved. The preparing method includes modifying a silk fabric with polycarboxylic acid, and assembling the MOFs synthesized from rare earth ions and micromolecule polycarboxylic acid onto the surface of the fabric through a hydrothermal reaction to form nanometer crystal grains, nano-cluster or nanolayer-thick fluorescence film with different types of morphology. The rare earth ions mainly adopt Eu ions with pure red light emission and Tb ions with green light emission. A small organic molecule ligand and the silk fabric mainly emit blue and purple light. According to the trichromatic theory, fluorescence with any color can be formed through adjustment. The method is simple, feasible, short in period, high in efficiency, and free of pollution, is a fabric surface nanometer treatment technique with a wide application prospect, and can prepare the silk fabric with a plurality of adjustable fluorescence colors.