The invention provides a potentiometer which comprises a shell, a rotating shaft, a rotating mechanism 1, a rotating mechanism 2, a carbon plate and three carbon plate terminals arranged on the carbon plate, wherein the surface of the carbon plate is provided with an inorganic oxidized metal nano layer; an electronic transmission layer is arranged on the inorganic oxidized metal nano layer; and an admittance layer is arranged on the electronic transmission layer. The potentiometer with the carbon plate has the advantages of fewer switching parts and favorable high-temperature resistance, can not deform at high temperature, and overcomes the defect of high deformation tendency of riveting at high temperature. The carbon plate surface is provided with the inorganic oxidized metal nano layer, the electronic transmission layer is arranged on the inorganic oxidized metal nano layer, and the admittance layer is arranged on the electronic transmission layer. The inorganic oxidized metal nano layer arranged on the carbon plate can enhance the conduction efficiency of the carbon plate, thereby enhancing the hole mobility. The energy bands can form the energy level gradient, thereby being beneficial to the transmission rate in the transmission layer and enhancing the electron conductivity of the potentiometer.