Dissimilar joining of lapped E36 steel plates to aluminum alloy 5083 sheets was carried out by using laser keyhole welding process with the addition of Ni, Zn and Sn filler powders. By using optical microscopy, scanning electron microscopy, energy disperse spectroscopy, the microstructures and microscopic hardness of the welded joints with the filler powders were studied. The results show that the addition of powders into the weld joint can improve the morphology of the intermetallic compound (IMC), reduce the thickness of Fe-Al IMC, and finally improve the ductility and toughness of the weld joints.