Aluminum nitride (AlN) ceramics are excellent materials for electronic packaging substrates. Selective surface laser metallization can simplify the manufacturing process of AlN substrates, shorten the manufacturing period and reduce the manufacturing cost. As conductivity of laser metallization layers cannot meet requirements for printed circuits of high-power devices, this paper carried out a systematic laser process experiment, aiming to find a way to improve the conductivity of the laser metallization layer on the surface of AlN ceramics. AlN ceramic samples used in this study was a commercially available ceramic sheet with a purity of 98wt.%, with a size of 25 mm×15 mm×1 mm. The laser scanning area was a rectangle with a size of 8 mm×1 mm. The ceramic test pieces were first rinsed with distilled water, then ultrasonically cleaned with absolute ethanol for 10 min, and dried in cold air for use. The laser equipment was a 30 W nanosecond fiber laser marking machine. The Taguchi method was adopted and a L16 (43) orthogonal scheme was selected. Three process parameters were laser power (12-30 W), frequency (20-50 kHz) and scanning speed (100-700 mm/s), respectively. Resistance values of laser metallization area was measured through the four-terminal method. The laser scanning areas under the orthogonal test parameters all had lower resistances. The resistance value of T14 sample was the smallest, which was 18 Ω (line resistance 2.25 Ω/mm); the resistance value of T1 sample was the largest, which was 220 Ω (line resistance 27.5 Ω/mm). It showed that the combination of process parameters in this study could make AlN surface laser-metallized. Laser power had the most significant effect on the resistance of the laser metallization layers of AlN samples within the process parameters and their value ranged in this study. The optimized process parameters based on the minimum resistance value were:laser power 30 W, frequency 30 kHz, and scanning speed 100 mm/s. The resistance value of the metal layer on the aluminum nitride surface prepared by single laser scanning with the optimized process parameters was 2.25 Ω/mm. With laser scanning number increased, resistance value of the metallized layer changed to the opposite direction:resistance decreased rapidly for the low-power laser process, while resistance increased rapidly for the higher-power laser process. After laser scanning for 10 times, the resistance value of the laser metallized layer with a laser power of 3 W (corresponding to a laser energy density of about 15.3 J/cm2) was lower than those of with laser power of 30 W and 18.75 W. Under the experimental parameters of this study, the resistance of the laser-metallized layers decreased with the increase of the laser fluence. It is worth pointing out that as the laser energy density in this study is mainly concentrated in 30-100 J/cm2, the optimum fluence and minimum achievable resistance cannot be determined. It suggests from this study that a single scan with a higher power laser or multiple scans with a lower power laser is beneficial to improve conductivity of laser laser-metallized surface layers of AlN substrates.