Abstract: Carbon nanotubes(CNTs) coated by Ni/AM60 magnesium alloy composite was fabricated by mechanical stirring casting technology.The effect of carbon nanotubes content on the mechanical properties of as-cast composites was studied.The microstructure and fractographs were observed and analyzed by using scanning electron microscopy.The results show that the microstructure of the composite was equiaxed grains and the CNTs coated by Ni mainly distributed on the eutectic phase and eutectic boundaries,which not only had the role of refining grains,but also played the role of lapping grains and strengthening grain boundaries.Mechanical properties of the composite first increased and then decreased as the CNTs addition increased when the mass fraction was 1%.The tensile strength,microhardness and elongation were maximized at the same time,increased 46.23%,41.82%,7452% respectively compared to the AM60 magnesium alloy.The elastic modulus was maximized when mass fraction was 1.2%.