A method for purification and lattice reconstruction of graphite in a power battery, comprising the following steps: obtaining electrode material powder, copper powder, aluminum powder and iron powder respectively by sequentially subjecting a waste power battery to discharging, coarse breaking, pyrolysis, fine breaking and sorting; obtaining a filter residue A by performing following operations: mixing the electrode material powder with a metal extractant, standing still, then washing with a purifying agent A, and filtering; obtaining a crude graphite by performing following operations: mixing the filter residue A with the metal extractant, standing still, then washing with a purifying agent B, and filtering; obtaining a primary purified graphite by subjecting the crude graphite to a de-organic treatment, cooling, ball milling, and ventilation replacement; and repairing graphite lattice by introducing a rare gas into the primary purified graphite; wherein in step, the purifying agent A is a mixed solution of hydrochloric acid, ethanol and acetone, and the purifying agent B is a mixed solution of deionized water, ethanol and acetone; wherein the repairing graphite lattice in step comprises: introducing a rare gas at a flow rate of 5-30 mL/min within 40-80 min, closing an inlet valve and an outlet valve, and heating to a temperature of 2400°C-2600°C at a heating rate of 10-20°C/min, keeping the temperature for 10-30 min, then heating to 2600°C-3200°C at a heating rate of 3-10°C/min, and repairing the graphite having damaged lattices within 6-10 h; wherein the de-organic treatment in step comprises placing the crude graphite in a vacuum furnace at a heating rate of 1-5°C/min to be heated to 200°C-250°C for the de-organic treatment for 2-4 h; wherein the replacement in step comprises introducing a replacement gas at a flow rate of 5-30 mL/min, and then heating to 250°C-450°C at a heating rate of 1-5°C/min for replacement for 20-40 min; wherein the rare gas in step is He with a volumetric purity of 99.999%. obtaining electrode material powder, copper powder, aluminum powder and iron powder respectively by sequentially subjecting a waste power battery to discharging, coarse breaking, pyrolysis, fine breaking and sorting; obtaining a filter residue A by performing following operations: mixing the electrode material powder with a metal extractant, standing still, then washing with a purifying agent A, and filtering; obtaining a crude graphite by performing following operations: mixing the filter residue A with the metal extractant, standing still, then washing with a purifying agent B, and filtering; obtaining a primary purified graphite by subjecting the crude graphite to a de-organic treatment, cooling, ball milling, and ventilation replacement; and repairing graphite lattice by introducing a rare gas into the primary purified graphite; wherein in step, the purifying agent A is a mixed solution of hydrochloric acid, ethanol and acetone, and the purifying agent B is a mixed solution of deionized water, ethanol and acetone; wherein the repairing graphite lattice in step comprises: introducing a rare gas at a flow rate of 5-30 mL/min within 40-80 min, closing an inlet valve and an outlet valve, and heating to a temperature of 2400°C-2600°C at a heating rate of 10-20°C/min, keeping the temperature for 10-30 min, then heating to 2600°C-3200°C at a heating rate of 3-10°C/min, and repairing the graphite having damaged lattices within 6-10 h; wherein the de-organic treatment in step comprises placing the crude graphite in a vacuum furnace at a heating rate of 1-5°C/min to be heated to 200°C-250°C for the de-organic treatment for 2-4 h; wherein the replacement in step comprises introducing a replacement gas at a flow rate of 5-30 mL/min, and then heating to 250°C-450°C at a heating rate of 1-5°C/min for replacement for 20-40 min; wherein the rare gas in step is He with a volumetric purity of 99.999%. wherein the repairing graphite lattice in step comprises: introducing a rare gas at a flow rate of 5-30 mL/min within 40-80 min, closing an inlet valve and an outlet valve, and heating to a temperature of 2400°C-2600°C at a heating rate of 10-20°C/min, keeping the temperature for 10-30 min, then heating to 2600°C-3200°C at a heating rate of 3-10°C/min, and repairing the graphite having damaged lattices within 6-10 h; wherein the de-organic treatment in step comprises placing the crude graphite in a vacuum furnace at a heating rate of 1-5°C/min to be heated to 200°C-250°C for the de-organic treatment for 2-4 h; wherein the replacement in step comprises introducing a replacement gas at a flow rate of 5-30 mL/min, and then heating to 250°C-450°C at a heating rate of 1-5°C/min for replacement for 20-40 min; wherein the rare gas in step is He with a volumetric purity of 99.999%.