Abstract: Multi-walled carbon nanotubes（MWNTs）,having a diameter around 10~20 nm,were used as reinforcement for electrodeposition of Ni.Compact and smooth Ni-carbon nanotubes composite coatings were prepared by electrodeposition in Ni plating bath containing homogeneously dispersed carbon nanotubes with the aid of interval ultrasonic agitation and air agitation.The morphologies of the composite films were observed on a scanning electron microscopy（SEM）,and roughness was tested on stylus profiler.The hardness of the films was examined on the microhardnss instrument and nanohardness instrument respectively.Tensile strength of the thin composite film was measured on a new micro-tensile device.It was found that the introduction of MWNTs in the electrodeposition of Ni with the aid of interval ultrasonic agitation and air agitation would greatly increase the hardness of the composite films,which reached its climax when the content of MWNTs was around 4%.The tensile strength of the composite film is also slightly improved,The SEM image of the fracture prove this reinforcement effect.