The invention belongs to an ink jet printing (jet printing for short) circuit technology, relating to a primary circuit or microwave processing primary circuit prepared by jet-printing metal conductive printing ink by utilizing a laser sintering method, and aiming at degrading organic components in the printing ink and improving conductive properties of the obtained jet printing circuit. In the method for preparing the primary circuit by printing the metal conductive printing ink by virtue of laser or microwave processing, laser continuous scanning, exposing and sintering, selective scanning, exposing and sintering, overall exposing and sintering or selective exposing and sintering are carried out on the primary circuit prepared by jet-printing the metal conductive printing ink, or the primary circuit prepared by jet-printing the metal conductive printing ink is sintered by virtue of microwave processing, so as to improve electric conductivity of the jet-printed circuit; the jet-printed primary circuit is processed by utilizing the laser with high speed, high efficiency and positioning accuracy, thus being applicable to extensive printing boards or films; and requirements on material and shape (hard board or film) of the printing board or film are not strict, and thus the method is applicable to automation.