Abstract: FeCrBSi alloyed coatings was prepared on Q235 steel substrate directly by plasma spraying process. The effect of plasma spraying process parameters on the bonding strength of the coatings was studied by orthogonal test method,and the process parameters were optimized at the same time. Then the effect of coating thickness on the bonding property of the coatings was also studied on the basis of optimized parameters. The results show that the best process parameters for plasma spraying FeCrBSi alloyed coatings were spraying electric current of 900 A,main gas flow of 44.8 L·min-1,assist gas flow of 27.8 L·min-1 and spraying distance of 110 mm. Bonding strength between the substrate and the coating,and inside the coating of the sample sprayed by optimized parameters was 18.2 MPa and 33.5 MPa separately. With the increase of coating thickness,bonding strength between the substrate and the coating decreased obviously,but the bonding strength inside the coating first increased and then decreased. The optimized coating thickness was 347.2 μm.