The invention discloses a filtering material for treating printing and dyeing wastewater and preparation method thereof; the filtering material is good in filtering effect, easy to clean and long in service life. The filtering material of the embodiment comprises a first fiber mesh layer, a first carbon nanotube paper layer, a base cloth layer, a second carbon nanotube paper layer and a second fiber mesh layer which are connected in order; the surface of the base cloth layer is deposited with graphene quantum dots. The preparation method includes a step S10 of modifying the first fiber mesh layer, the base cloth layer and the second fiber mesh layer; a step S20 of depositing the graphene quantum dots on the surface of the base cloth layer, and then orderly arranging the first fiber mesh layer, the first carbon nanotube paper layer, the base cloth layer, the second carbon nanotube paper layer and the second fiber mesh layer; fixedly connecting every layer and forming a filtering material base body; a step S30 of immersing the filtering material base body in the mixed solution containing AgNO3 and graphene quantum dots, and then irradiating the immersed filtering material base body under sunlight or ultraviolet light, and obtaining the filtering material.