High chromium cast iron alloys are widely used to produce wear resistant components. However, formation of the large carbides restricts their applied range for the components by traditional solidification techniques. The gas atomization is an effective approach to refine their structures, improve their properties and extend their application field. Based on the study of structure evolution of atomized powders of Fe-25Cr-3.9C alloy, this paper investigated the structure evolution of the atomized powders of Fe-25Cr-3.9C alloy with addition of Ni and B elements. It is found that addition of Ni and B elements make more primary lath-shaped phase be formed. As particle size decrease, width of the primary lath-shaped phase gradually decreases, and the structures are all composed of lath-shaped phase in the small powders with diameter less than 38mm. At last, a relative study between two alloys was made, and the structure formation of atomized powders was discussed.