<p>M50NiL bearing steel specimens are produced by the laser powder bed fusion technology (LPBF), and the machinability and microstructural characteristics of bearing steel for LPBF have been investigated. Through the single-factor variable approach, the influence of laser power, scanning speed and scanning spacing on the relative density is analyzed, and the desirable process parameters window is obtained. It is found that within a reasonable range, the relative density of the sample is positively correlated with the laser power and negatively correlated with the scanning speed. The combination of high power and low scanning speed can also induce hump phenomenon, which is not conducive to the improvement of density. The hatching space should be reasonably set according to the width of the single melt track and the heat accumulation effect in the printing process. The ideal process parameter window as follows: 210-280 W of laser power, 500-800 mm/s of scanning speed, hatching space between 0.08-0.12mm, layer thickness of 0.04 mm, and strip-zoning scanning strategy with a rotation of 67°between layers. The relative density reaches a peak value of 99.64 % when the volume energy density is 88 J / mm. The molten pool structure of LPBF state M50NiL steel as a whole shows obvious non-uniformity characteristics, which mainly composed of columnar crystals with high dislocation density, and equiaxed crystals appear in the overlapping area of the molten pool. There are two sources of equiaxed crystals, namely solid-state recrystallization and the fragmentation of columnar crystals. The heat-affected zone outside the molten pool is a solute element-rich zone. The microstructure is lath martensite matrix + unevenly distributed nano-precipitates, with the precipitated phases mainly being metastable phases such as V₃Cr₂C₅, V₂C and Fe₃Mo₃C.</p>