The invention discloses a method for washing graphite piece in a thermal field of a Czochralski single-crystal furnace. The method is implemented by the following specific operation steps of: mounting the graphite piece; starting a furnace body cooling water circulation system and a power supply cooling water circulation system of a high-temperature induction furnace respectively; vacuumizing; heating including a preheating process and a heating process, carrying out the heating process according to a temperature rise manner of 100 DEG C per hour during temperature rise before realizing 1,000 DEG C, carrying out the heating process according to a temperature rise manner of 50 DEG C per hour during 1,000-2,000 DEG C temperature rise, and carrying out the heating process according to a temperature rise manner of 30 DEG C per hour during 2,000-2,400 DEG C temperature rise; uniformly cooling the interior of the high-temperature induction furnace from 2,4000 DEG C to 80-100 DEG C as the temperature of furnace discharge; and discharge the graphite piece. According to the method for washing the graphite piece in the thermal field of the Czochralski single-crystal growth furnace, disclosed by the invention, SiC reacts at high temperature so that the service life of the graphite piece is prolonged to be 15-30 furnaces, and the method disclosed by the invention is suitable for washing each graphite piece in the single-crystal furnace.