Nickel hydroxide was deposited on the surface of modified carbon nanotubes（CNTs）by improved precipitation process with nickel sulfate and ammonia as well as CNTs as raw materials

and NiO/CNTs composites were obtained by thermo-decomposition at 450℃.Properties and microstructure of the NiO/CNTs composites with different carbon nanotubes were examined by scanning electron microscopy（SEM）

X-ray diffraction（XRD）and transmission electron microscopy（TEM）.Then NiO/CNTs powder was added to Mg-Zn alloy.The results indicate that nano nickel oxide prepared by homogeneous precipitation method can adhere with carbon nanotubes well.With 33% nickel oxide

carbon nanotubes can be coated by nano nickel oxide uniformly

and the average diameter of nickel oxide particles reaches 20 nm with absence of agglomeration and acceptable disperserdly distrbution.Compared with adding carbon nanotubes directly

carbon nanotubes coated nickel oxide are more easily to be added into magnesium-zinc alloy

which can refine grain size and improve hardness of the composites.