With the improvement of design parameters of steam turbine,the demands for high-temperature materials and related surface modification technology are becoming increasingly strong. GH901 material and its nitriding and cladding parts are also widely used in high temperature oxidation resistance and high temperature wear resistance working conditions. In this paper,plasma spray welding（PTA） is used to test stellite alloy on GH901. The effect of welding single and double stellite alloy on the microstructure and properties of the HAZ of the welded joint is studied. The results show that when using PTA method to weld Stellite,a large diffusion area of components is easy to form at bond line of the joint,and a large number of precipitates such as TiC are produced in the grain and at the grain boundary of the diffusion area. With the welding heat sequence of the two layers,the width of the diffusion area between the welding layer and the matrix increases,and the number and size of precipitates also increase.