In order to improve the bonding strength of the surface coating of the deflector and prolong its service life,four kinds of Ni-Al composite coatings were prepared on 6061-T6 aluminum alloy by twin-wire arc spraying technology. The bonding strength properties of four different composite coatings were studied. At the same time,the appearances of fracture and section of the coating were observed,and the failure reasons were analyzed. The results show that the bonding strength of Ni-Al composite coating with Ni-5 wt.%Al as bottom layer and Ni-20 wt.% Al as surface layer is higher,and the bonding strength of the composite coating meets the performance index requirements.