Parts made of additive are anisotropic due to layer by layer manufacturing.In order to study the effect of building direction on the erosion wear performance,the laser coaxial powder feeding process was used to prepare the Fe-based alloy cladding layer by layer,and the microhardness,metallographic structure,microstructure of the Fe-based cladding layer and the surface morphology after erosion were analyzed.The results of microscopic observation on horizontal surface (XY),cross section (YZ) and longitudinal section (XZ) show that the microstructure of each direction is closely related to the direction of heat flow and fusion line,and thus significantly affects the distribution and size of fine grain areas.The average microhardness of the horizontal surface of the deposited clad layer is the largest,the average microhardness of the cross section is the second,and the average microhardness of the longitudinal section is the lowest.Due to the work hardening in the process of erosion,the difference of erosion wear performance between different building directions is weakened,which leads to similar erosion wear morphology in each building direction.The results of erosion wear test show that the erosion mechanism of the deposited clad layer is mainly micro cutting and ploughing.The horizontal surface of the deposited clad layer has the best erosion wear resistance,and the longitudinal section has the worst erosion wear resistance.