Compositionally graded samples were fabricated from pure Fe to Fe20Cr (mass fraction, %) through laser powder bed fusion and in-situ alloying using a blend of Fe and Cr elemental powders as feedstock. The compositional homogeneity, phase structure, microstructure morphology, and microhardness of the component area with different Cr contents were investigated. The results revealed that the gradient composition sample was well alloyed, and the maximum average deviation of all the composition gradients was 0.35%. X-ray diffraction analysis revealed that the composition gradients had a body-centered cubic structure. The microstructure of pure Fe consisted equiaxed grains, and with the increase of Cr content, the transformation from equiaxed to columnar grains occurred between Fe10Cr and Fe12Cr. Furthermore, the grain-boundary strengthening effect of equiaxed grains can effectively enhance the microhardness of the samples, with Fe10Cr having the highest microhardness among all composition gradients at 181 HV_0.5.