The work aims to apply Al2O3/Ni nano composite brush electro-plating technology to repair and remanufacturing of damaged engine camshaft. Composite plating solution was obtained by adding nano Al2O3 power and dispersants including triammonium citrate and cetyltrimethylammonium bromide into high speed nickel-plating solution. Then the composite plating solution was heated and stirred on a constant temperature magnetic stirrer until the temperature of composite plating solution reached 50 ℃ and Al2O3 nano powers suspended steadily. The brush electro-plating technology was adopted to coat the composite plating solution on the surface of 45# steel plate made from materials identical to those of engine camshaft. The influences of brush plating voltage and mass concentration of Al2O3 nano power on surface morphology and surface hardness of the composite coating were evaluated based upon surface observation and hardness test, respectively. Hardness of the composite coating was higher than that of 45# steel, and surface hardness increased with the increase of brush plating voltage and concentration of Al2O3 nano power. As the plating voltage was over 10 V, surface hardness decreased with the increase of concentration of Al2O3 nano power increased. Surface cracks of the composite coating increased with the increase of the brush plating voltage and concentration of Al2O3 nano power. The lower the concentration of Al2O3 nano power was, the greater the influence of brush plating voltage on surface hardness of the composite coating was. The influence of the brush plating voltage on the surface hardness of the composite coatings was greater than that of mass concentration of Al2O3 nano power. Surface hardness of the camshaft can be improved by applying the Al2O3/Ni nano composite brush electro-plating technology to repair damaged camshafts. In order to improve the surface quality of camshafts and prevent surface defects such as surface porosity and coke paste from affecting surface hardness, automatic nano brush electro-plating plating equipment should be developed, and the plating process in different coating alternatively overlay method shall be adopted.