Abstract: Capacitive deionization (CDI) is an effective method for removing ions from saline water. It has many technical advantages such as low energy consumption and no secondary pollution. The properties of electrode materials are the key factors that determine CDI performance. The boron nitride-carbon nanosheets were synthesized by a high-temperature solid-state method and had a high specific surface area and good electrochemical stability. A boron nitride-carbon nanosheet/graphene composite with high desalination ability and excellent cycling stability was prepared by covalent cross-linking. In this composite, boron nitride-carbon nanosheets provide abundant adsorption sites for Na⁺ ions, and the excellent electrochemical stability improves the CDI cycle performance while the graphene forms an electronic conduction network, which increases the conductivity of the composite electrode. An asymmetric CDI cell using the composite as the anode and activated carbon as the cathode exhibits an excellent salt adsorption capacity of 20.16 mg g^-1 at a supplied voltage of 1.4 V when the feeding NaCl concentration is 3 200 mg L^-1. After the cell has been cycled 30 times with an initial NaCl concentration of 3 200 mg L^-1 at a supply voltage of 1.0 V, its capacity is 88.1% of the initial value.