Abstract: The 2205 duplex stainless steel layer was prepared on the surface of Q345 steel substrate by plasma arc cladding. The effects of cladding speed (3-7 mm·s^-1), cladding current (83-117 A), wire feed speed (43-77 mm·s^-1) and their interaction on the dilution rate and width to height ratio of the cladding layer were studied by response surface methodology, and the optimal plasma arc cladding process was obtained. The results show that using small cladding current and high wire feed speed could obtain the cladding layer with low dilution rate, using large cladding current and low wire feed speed could obtain the cladding layer with high width to height ratio, and the cladding speed had little effect on dilution rate and width to height ratio. The optimized process parameters were listed as follows: cladding current of 99 A, cladding speed of 6 mm·s^-1, wire feed speed of 50 mm·s^-1. Meanwhile, the dilution rate and width to height ratio were 14.8% and 4.36, respectively. The relative errors of the predicted dilution rate and width to heigth ratio with the test values were 2.9% and 2.3%, respectively, indicating that the quadratic mathemitical model established by response surface methodology was reliable. The cladding layer prepared by the optimal process had a good forming performance.