Disclosed is a novel method for ink jet printing on a surface of a substrate made of a synthetic resin, the method comprising the steps of conducting a surface treatment to the surface so as to provide it with a specific surface free energy of 65-72 mJ/m 2 ; providing an activation energy beam-curable ink having a surface tension of 25-40 mN/m; discharging the ink onto the surface with an ink jet printing device thereby forming printed portions of the ink on the surface; and projecting an activation energy beam onto the printed portions. According to the disclosed method, printing articles having desirable image qualities are obtained by achieving a uniform dot diameter of the drop of ink on a synthetic resin substrate by utilizing an ink jet printing process.