The invention belongs to the field of modification of Mxene materials, and discloses an Mxene material with an organic chelating functional group grafted on the surface, the Mxene material is combined with a grafting agent through a silicon-oxygen bond, and the grafting agent contains amino and/or carboxyl as the organic chelating functional group. The invention also discloses a preparation method of the Mxene material. The preparation method comprises the following steps: S1, dispersing Mxene powder in an organic solvent to obtain a suspension I, and adding the grafting agent into an organic solvent to obtain a solution II; and S2, adding the solution II into the suspension I, carrying out stirring reaction under an ultrasonic condition, then separating out a solid, and carrying out cleaning and drying to obtain a product. The preparation process is controllable and simple, operation is easy and convenient, the material is good in morphology and structure, the number of chelating functional groups grafted on the surface is considerable and uniform, and the material serving as a capacitive deionization electrode material is excellent in heavy metal ion and radioactive ion removal performance, so that efficient treatment of water is achieved, the material can be regenerated and recycled, and large-scale industrial production and application prospects are achieved.