The invention relates to high-purity graphite powder and a purification process thereof. The process comprises the following steps: adding a graphite powder raw material in a graphite boat, mounting the graphite boat in purification equipment, vacuumizing until the pressure is minus 83-minus 100 KPa, and maintaining pressure for 0.5-2 h; after pressure rise rate is qualified, heating to the temperature of 1200-1800 DEG C, feeding a certain amount of purified gas, and after maintaining the pressure, vacuumizing until pressure reaches minus 93-minus 100 KPa; during heating period, carrying out impulse type purification, insulating for 1-3 h at a certain temperature in a temperature range of 2000-3000 DEG C, and then stopping impulse type purification; and vacuumizing and cooling to the temperature of 1200-1500 DEG C, feeding argon and enabling the temperature to be reduced to a room temperature to obtain the high-purity graphite powder. According to the purification process, volatilizedimpurities can be discharged in time by an impulse type process at a low temperature, the problem that key impurities such as B, Al and V in the graphite powder raw material are removed deeply is solved, therefore, the high-purity graphite powder with the purity reaching 99.999%-99.9999% is obtained, and a feasible path is provided for industrialized production of the high-purity graphite powder.