Abstract: 【Objective】 Selective laser melting(SLM) facilitates the fabrication of molds integrated with conformal cooling channels, which significantly enhances cooling efficiency. Nevertheless, the thermal conductivity of current mold materials still remains inadequate. Although FeCoNi medium-entropy alloy demonstrates outstanding thermal conductivity, its mechanical strength is insufficient to meet practical application requirements. Notably, SLM technology holds substantial potential to regulate the alloy's microstructure and thereby improve its mechanical properties. As a core process parameter of SLM, the influence of laser scanning strategy on the FeCoNi alloy has not yet been systematically clarified. Therefore, this study aims to investigate the effects of different scanning strategies on the relative density, microstructure, and microhardness of FeCoNi alloy fabricated via SLM.【Method】 FeCoNi alloy specimens were fabricated using three distinct scanning strategies with inter-layer rotation angles of 0°, 67°, and 90°, under fixed SLM processing parameters of a laser power of 200 W, a scanning speed of 700 mm/s, a hatch spacing of 100 μm, and a layer thickness of 30 μm. The relative density, microstructure, grain size, and microhardness of the samples were characterized using Optical microscopy(OM), Scanning Electron Microscopy(SEM), Electron Backscatter Diffraction(EBSD), and a Vickers microhardness tester.【Result】 The scanning strategy shows a minor effect on the alloy's relative density. The sample fabricated with the 67° rotation strategy exhibits the lowest porosity(0.01%), achieving near-full density. The average grain sizes of samples produced with 0°, 67° and 90° rotations are 4.11 μm, 3.15 μm and 2.22 μm, respectively. The primary texture components correspond to the <001>, <111> and <101> orientations. The Vickers microhardness values for these three samples are 295 HV, 338 HV and 312 HV, respectively.【Conclusion】 This study demonstrates that the laser scanning strategy is an effective method for tailoring the microstructure and properties of SLM-fabricated FeCoNi alloy. Under identical volumetric energy density, the three scanning strategies alter the heat transfer during powder solidification. Compared with the 0° rotation strategy, the 67° and 90° rotation strategies induce more complex thermal behavior during fabrication, which forces the grain growth direction to continuously adapt to the changing temperature gradient. As a result, grain growth is altered and partially restrained, leading to a gradual reduction in grain size with increasing rotation angle. Furthermore, the rotating scanning strategies cause variations in the solidification rate of the melt pool along different directions, affecting the undercooling and nucleation rate during solidification, thereby ultimately modifying the grain size and promoting the formation of distinct strong textures. The microhardness of the SLM-fabricated FeCoNi alloy is primarily governed by its relative density, grain size, and texture strength. Defects generated during the forming process reduce the alloy density, and under stress, these defect sites are prone to stress concentration, which locally weakens the load-bearing capacity and thus lowers the hardness. Additionally, a stronger texture may correspond to a higher dislocation density within the crystals, which impedes dislocation motion and thereby increases material hardness. Furthermore, alloy strength typically increases with decreasing grain size. Consequently, the FeCoNi medium-entropy alloy fabricated using the 67° scanning strategy exhibits the highest microhardness, reaching 338 HV. This research provides crucial process guidance for fabricating high-performance, high-thermalconductivity mold materials via SLM.