The invention discloses a double-ion desalination electrode and a preparation method thereof. An MXene@NTO composite is adopted as an anode material, and a NiCo-Ox@graphene composite or a bamboo shootcarbonized material is adopted as a cathode material. The MXene@NTO comprises components of Ti3C2@Na4Ti5O12&Na4Ti9O20 and is prepared through the following steps: MXene is added to a NaOH solution with the concentration being 1-10 mol/L according to the amount that every 0.1 g of MXene is added to at least 10 ml of the NaOH solution, a hydrothermal reaction is conducted at 100-300 DEG C for 1-6 h, a product is left to stand, and the product is cooled to the normal temperature naturally; after the reaction product is filtered, the product is washed with deionized water at least twice, and vacuum drying is performed at 30-80 DEG C for at least 10 h to obtain the MXene@NTO composite. The prepared desalination electrode has regular pore structure, high effective surface area, high desalination amount, high desalination rate and low energy consumption, can be applied to preparation of a double-ion capacitor desalination electrode and can be assembled into a double-ion desalination batteryand applied to water environment treatment to rapidly and efficiently remove Na<+>, Cl<->, SO4<2-> and F<-> in water environments, and a new way is provided for low-energy-consumption and high-performance desalination.