Abstract: In order to develop special cladding powder for laser direct writing signs,and obtain convex shaped logo on weathering steel Q450NQR1 used in railway freight cars,based on uniform design and optimization,the composition of alloy powder was analyzed in theory and confirmed in experiments,and the data of appearance,hardness,corrosion weight loss and corrosion loss rate were obtained for different component.The results indicate that when the mass fraction of alloy composition is w(Ni)=0.20～0.22,w(Cr)=0.14～0.155,w(Si)=0.01～0.015,w(B)=0.005～0.006,and Fe as the remainder,the obtained cladding layer has beautiful appearance,metallurgical bonding with the substrate,and better atmospheric corrosion resistance than the base metal.The result is helpful for application of the system of laser direct writing signs on railway wagons industry.