Modified directed melt nitridation of pure Al block was investigated by using magnesium as an external dopant at 1373-1573 K during the flowing high pure N-2. The products were characterized using optical microscope, X-ray diffractometer, scanning electron microscope and electron probe microanalysis techniques. Experimental results show that it is a lower costs way to synthesize AlN matrix or Al matrix materials by modified directed melt nitridation through adapting proper processing parameters. The weight gain rate increased significantly with the treating temperature and Mg content. Apparent activation energy of 208.7 KJ/mole was obtained in terms of the reaction rate involving nitridation, evaporation and transportation. AlN reinforced Al matrix material was fabricated with less Mg and AlN particles were enriched in the top part of the product with distinct boundary to the bottom Al. however, when the content of Mg was up to 10 wt% and treated at higher treating temperature, AlN phase dominated in the product with a relative looser structure.