Abstract: Flux surface preparation on ZL101 substrate was carried out to form Ni5Al coating by plasma spray.The mechanism of the coating was analyzed by calculation for interfacial temperature.The effect of process parameters on bonding strength of the coating was studied by three-factor,three-level orthogonal experiments.The results show that preplacing flux prior to spraying can substantially improve the adhesion of the coating,and the temperature of sprayed particles and the substrate temperature play determinative roles in the interfacial bonding.The optimal process parameters are the spray distance of 120 mm,the specific quantity of prelaid flux of 80 mg/cm² and the preheating temperature of 573 K.