Energy demand with social development, scientific and technological progress has increased sharply, fossil energy is accelerating depletion, accompanied by environmental pollution problems are becoming increasingly prominent. As a new type of green energy storage device, supercapacitor can realize rapid energy conversion. In this paper, CoM-LDHs electrode material was prepared with a certain amount of n(Co):n(Ca, Ni, Mg) as raw material and urea as precipitator by co-precipitation method. The structure and properties of the sample were characterized by XRD, SEM and electrochemical tests. CoNi-LDHs has the largest specific capacitance, reaching 205.3 F·g−1 at the current density of 0.5 A·g−1, for the cation substitution center Ni(II) is oxidized by NiOOH on the surface. The proton can be diffused to the surface active site through the hydrogen bond in the middle of Ni(OH)2 or through the Ni-O structure to promote the reduction of Co(III) to Co(II), so as to achieve efficient energy storage. This material has important reference significance for the development of electrode materials for supercapacitors.