Abstract: Laves phase formed by Nb segregation during laser cladding of IN718 alloy is an important reason to induce cracks and reduce mechanical properties. The effect of laser power and scanning speed on the microstructure and Nb element segregation of IN718 alloy single layer single pass cladding layer was studied under constant powder feeding rate and focusing amount. The results show that the laser power and scanning speed have significant effect on the microstructure and element segregation of IN718 alloy. With the increase of the laser power, the dendrite structure gradually coarsens and Nb segregation intensifies, and the volume content of Laves phase increases and the morphology gradually changes from granular to massive and long chain. With the increase of the scanning speed, the dendrite structure is gradually refined and the Nb segregation is obviously inhibited, and the volume content of Laves phase decreases and its morphology gradually changes from long chain shape to granular shape.