The laser surface cladding technique was used to form a 30vol-% SiCp/Ni-Cr-B-Si-C composite coating on the AISI1045 steel substrate. The microstructure of the coating was investigated by SEM and TEM. SiCp had completely dissolved in the Ni based alloy during the laser processing. The bonding zone between the coating and the substrate had an eutectic structure, characterized by directional solidification and enrichment in Fe. The clad layer had a very fine microstructure which consisted of primary graphite G in the upper part of the Clad, closely spaced M23(C,B)6 dendrites in γ-Ni solid solution, and a small amount of lamellar eutectic Ni+Ni3(B,Si). TEM EDX compositional analysis showed a marked extension in solid solubility of Si in Ni solid solution because of the high cooling rate. M23(C,B)6 contains a high density of stacking faults. The microdiffraction pattern revealed a long periodicity of Ni3(B,Si).