The invention discloses a structure for preventing a thermocouple in a high-pressure single crystal furnace from being corroded or fused and relates to the field of preparation of semiconductor materials. The structure comprises a heater, a crucible, a crucible support, an upper crucible bar, the crucible and the crucible support are disposed in a heat field of a heater, the upper crucible bar is disposed at the bottom of the crucible support and is of hollow structure, the lower end of the crucible bar is provided with a sealing structure, a hollow chamber of the upper crucible bar forms a sealed chamber, and the thermocouple passes through the sealing structure so that a measuring end of the thermocouple is located at the inner top of the sealed chamber of the upper crucible bar; also provided with a hollow lower crucible bar, and an upper port of the lower crucible bar is in detachable fixed connection with a lower port of the upper crucible bar. The structure is effective in preventing corrosive or volatile gas from permeating the chamber of the upper crucible bar under high-temperature and high-pressure condition, preventing the measuring end alloy probe of the thermocouple being corroded or being fused due to melting point reduction caused by reaction with permeating gas, ensuring accurate feedback and display of temperature in the whole synthetic and crystal growth process, and increasing crystal material yield.