Carbon nanotubes (CNTs) have super-strong mechanical characteristics and unique hollow nanotube structure and are believed as very ideal materials for fabricating the excellent composites. In this study, Ni-P-CNT composite coatings with different contents of carbon nanotube (0.5-2.5 wt.%) on the surface of copper was proposed by electroless plating. The Scanning Electron Microscopy (SEM) was used to characterize the coatings. The SEM results showed that the thickness of the coatings was about 30µm and the deposited coatings had nodular features with a typical cauliflower-like structure and uniformly dispersed CNT in the nickel matrix. The effects of CNT concentration in the bath on the microstructure of the composite coatings, CNT content in the composite coatings and the hardness of composite coatings were studied. It was found that with increasing CNT concentration, both the CNT content in the composite coatings and the hardness of composite coatings increased at first and then decreased. The microstructural characterization was done by means of x-ray diffraction. It was found that the heat treatment induces structural changes. As-deposited coatings exhibit broadened x-ray reflections, which indicates a semi-amorphous structure. Heat treatment decreased the amorphous phase. In addition, the final equilibrium phases were Ni 3 P and Ni crystals with a nanocrystalline size. The maximum hardness was achieved in the specimens heat treated 400°C for 1.5 hours. The reason could be the formation of stable intermetallic Ni 3 P phase at this temperature, which acts as a precipitation hardener. The corrosion behavior of the composite coatings was evaluated by polarization curves and electrochemical impedance spectroscopy in 3.5wt% NaCl solutions at room temperature. It was found that the corrosion resistance of Ni–P-CNT composite coatings is excellent in comparison with that of Ni-P coatings. According to the results, with increasing the CNT concentration, corrosion rate decreases at first and then increases. The results showed that the incorporation of CNT in Ni-P coatings is advantageous for formation of better passive films. The corrosion resistance of the coatings indicates that increasing the temperature to 400°C leads to an increase in corrosion resistance followed by a decrease in higher temperatures. Heat treatment at the temperatures less than 400°C leads to the crystallization of the amorphous phase. This phenomenon results in the increase in the number of grain boundaries which is suitable for nucleation of passive film. Therefore, the heat treatment of electroless Ni-P-CNT composite coatings at the temperatures less than 400°C forms denser passive films and significantly increases their Keywords Carbon nanotube, Electroless plating, Composite, Corrosion, Wear, Friction coefficient.