The invention relates to a method for the chemical finishing of the surface defect of a diamond cutter by atmosphere low-temperature plasma, which belongs to the method for the chemical finishing of the surface defect of the diamond cutter by the atmosphere low-temperature plasma, aiming at solving the problem that after the diamond cutter at present adopts mechanical type grinding to carry out processing, microscopic defects existing on the grinding surface and a cutting edge of the cutter can not be removed, which influences the cutting performance and the service life of the diamond cutter. In the method, a mixture of plasma gas and reacting gas is introduced between a cathode and an anode of a plasma generator, a radio-frequency power signal is applied to the cathode and the anode, then plasma discharge is generated between the two electrodes, the diamond cutter after being ground is taken out after the diamond cutter is put in a plasma discharge area and processed for 10 minutes to 30 minutes, the finishing of the cutter can be realized, and circulating cooling water is introduced into hollow cavities in the electrodes. The invention is used for removing the surface microscopic defect of the diamond cutter.