The aluminum alloys AA5052, AA5083 and Al-7%Si (AC4C) were nitrided by electron beam excited plasma (EBEP) technique to improve wear resistance and hardness. The specimens were characterized with respect to the following properties: wear resistance, hardness of nitrided layer (AlN layer), surface and cross sectional microstructures. The friction coefficient of nitrided AA5052 decreased to 0.2 and that of Al-7%Si was improved to 0.1. The AlN layers were relatively uniformly formed on the AA5052 and AC4C alloys with a thickness of 4.5 μm and 2.5 μm during 2hrs and 5.4 ks, respectively. On the surface of nitrided AA5083, a uniform AlN layer was not formed due to the high nitriding temperature. The Si3N4 was found in the nitrided AC4C alloy.