Abstract: Supercapacitor has the advantages of high power density,long life and low production cost,which is considered to be one of the most promising energy storage systems. However,the practical application of supercapacitors is prevented due to its low energy density.Because the stored energy is directly proportional to CV2,the energy density of the supercapacitor can be increased by increasing the capacitance " C" of the material or the operating voltage window " V" or both. Organic electrolytes with wide potential windows in batteries have poor ionic conductivity,high cost,and easily cause environmental problems. Therefore,in order to improve the energy density,an electrode material with a high specific capacitance should be used. Therefore,the design of suitable electrode materials with high specific capacitance has become a research hotspot. As a supercapacitor electrode material,Ni(OH)_2 has attracted more and more attention in recent years due to its outstanding theoretical capacity,low cost,natural richness and easy synthesis. However,since Ni(OH)_2 has a low conductivity and a small surface area,its capacity is deteriorated severely. Carbonaceous materials are electrode materials for electric double layer supercapacitors,and their energy storage mechanism depends on the dissociation of the electrode surface and the adsorption of electrolyte ions. It is widely used due to its good conductivity,abundant raw materials,low cost,and high electrochemical stability. Therefore,it is necessary to make composite of Ni(OH)_2 with a highly conductive carbonaceous material to improve the capacitance performance. In this paper,the synthesis of Ni(OH)_2-based materials was reviewed,especially for the synthesis of Ni(OH)_2 combined with different carbonaceous materials to improve their cycle stability and rate performance as electrode materials.