Abstract: Weldability of particles reinforced aluminum metal matrix composite (Al MMCs) is analyzed from the point of view of chemical and physical allowability. Adaptability of fusion welding, brazing and solidstate bonding to the joining of Al MMCs is reviewed.The principle of friction stir welding (FSW) is introduced and the effects of FSW parameters on the weld shapes, microstructure and mechanical property of joints are discussed. The experimental result shows that FSW has the superiority in joining of particles reinforced Al MMCs.