The correlation occurring between reading quality or marking time of data matrix (DM) code marked on aluminium alloy and laser marking parameters has been studied, and the influence of laser parameters on DM code contrast is analyzed. The experiment result indicates that the optimal laser parameter domain is not simply distributed within a connected real neighborhood, but distributed in a union set of several connected real neighborhoods. The restricted space of laser parameter based on reading quality of DM code is built, and the laser marking process parameters combination with the goal of comprehensive optimal reading quality and marking time is acquired based on this foundation. Meanwhile, scanning electron microscope images and energy dispersive spectrometer data of DM code marked by the optimal parameter module are analyzed, which can explain the distribution of optimal laser parameters in microcosm.