A method for preparing a composite metal-organic framework material UiO-66 is disclosed. The method includes S1) ultrasonically dispersing ZrCl4 into DMF, and adding hydrochloric acid to obtain a liquid mixture A; S2) ultrasonically dispersing H2BDC into DMF to obtain a liquid mixture B; S3) mixing the liquid mixtures A and B, and reacting the obtained mixture in a reaction kettle with a polytetrafluoroethylene liner for 24 h to obtain a white precipitate; S4) washing the white precipitate with DMF and ETOH respectively and performing suction filtration to obtain a product; S5) drying the product in a vacuum drying oven to obtain UiO-66; S6) preparing an SRB mother liquor for later use, and diluting the mother liquor; S7) drying the UiO-66 in a vacuum drying oven; and S8) adding the UiO-66into the SRB solution, then allowing the mixture to stand in a water bath for 24 h for impregnation, and finally drying a product in a vacuum drying oven to obtain a UiO-66@SRB composite fluorescentmaterial. The method has advantages that UiO-66 and SRB are combined, and stable-structure UiO-66 pores of which can disperse SRB to avoid aggregation caused quenching is prepared.