The invention discloses an inorganic-organic hybrid europium phosphate photochromic material synthesis method, which comprises: carrying out a reaction on a mixture of an europium-containing metal source, an organic ligand, an acid and DESs for 2-11 days at a temperature of 100-150 DEG C under a sealing condition, wherein the acid is phosphoric acid or phosphorous acid, the DESs are one selected from choline chloride and oxalic acid, choline chloride and malonic acid, choline chloride and diglycolic acid, choline chloride and citric acid, and choline chloride and ethylene glycol, and a molar ratio of the europium-containing metal source to the organic ligand to the acid to the choline chloride in the DESs is 0.5-2:1-2:0.5-8:5-20. According to the present invention, the synthesized inorganic-organic hybrid europium phosphate photochromic material can be used for inkless erasable printing and multiple anti-counterfeiting, has characteristics of fast photo response and long color retention time, and can be recycled.