The invention provides a long-life reference electrode suitable for a deep-sea high-hydrostatic pressure environment. The long-life reference electrode comprises a housing, an inner electrode core, a salt bridge and a diaphragm, wherein the inner electrode core, the salt bridge and the diaphragm are arranged in the housing from top to bottom. The long-life reference electrode is characterized in that the salt bridge comprises saturated potassium chloride sol-gel and potassium chloride particles uniformly dispersed in the saturated potassium chloride sol-gel; the diaphragm is a supermicroporous ceramic column; an upper end of the inner electrode core is provided with an epoxy sealing filler; the upper end of the inner electrode core is connected to an electrode lead which passes through the epoxy sealing filler and is drawn out of the housing; a lower end of the inner electrode core contacts with an upper end of the salt bridge; a lower end of the salt bridge contacts with one side of the diaphragm which is the supermicroporous ceramic column; and the other side of the diaphragm is connected to the external world. The long-life reference electrode can satisfy electrochemical measurement requirements in a deep-sea high-hydrostatic pressure environment, can be widely used for corrosion signal monitoring and detection, electrochemical protection and equipment probe automatic control of marine structures, deep sea petroleum pipes and deep sea detection equipment.