Supercapacitor has the advantages of high power density, long cycle life, fast charging and discharging speed, which has great application potential in the field of energy storage. Electrode materials, as the core materials of supercapacitors, have crucial impacts on the performance of the whole energy storage system. Nickel hydroxide (Ni(OH)2) has the advantages of low cost, abundant reserves, high theoretical capacity, environmental friendliness, and high stability in alkaline electrolytes, which is often used as the electrode material for supercapacitors. However, there are still problems needed to be solved urgently, such as low conductivity, poor dispersion, limited specific surface area, and volume shrinkage during the charging and discharging process of supercapacitors. This paper reviewed the research progress in the past five years of the prepared Ni(OH)2-based composites, such as composites with carbon materials, metal oxides, metal sulphides, metal selenides, and hydroxide materials, and the influence of their micro-nano structures on the electrochemical performance was analyzed and discussed. The current issues and prospects for further study of Ni(OH)2-based composites in supercapacitors were summarized.