In the experiment, Fe76cr12mn12n alloy powder was prepared by mechanical alloying. The mechanical alloying process and mechanism were studied. The results show that the powder can be fully alloyed after 4 hours of rod milling. The diffraction peak widens and the diffraction intensity decreases with the increase of rod milling time,. The morphology of the powder particles gradually became spherical. The non-spherical solid solution powders obtained by mechanical alloying can also be used in laser melting deposition (LMD) additive manufacturing technology, which solves the limitation of LMD to spherical powder. The thick cladding coating obtained by LMD technology has good corrosion resistance, and it shows BCC+ FCC dual phase structure. Meanwhile, Cr2N is generated in the printing process. the Vickers hardness of thick coating could reach up to 456.3 HV.