The microstructure of the laser cladding coating with pre-placed B4C and B4C+Ti powders on TC4 substrate was analyzed using XRD, SEM and EDS. The results showed that both the coatings consisted of TiB2, TiB, TiC1-x and Ti phases. Some of Ti in the substrate was melted and mixed into the laser melting pool and reacted with B4C in-situ producing TiB, TiB2 and TiC1-x. The in-situ produced TiC1-x shows morphology of dendrite. The in-situ produced TiB2 shows morphology of whisker with larger size. The in-situ produced TiB shows morphology of whisker with smaller size. The bonding between the coating and TC4 alloy substrate was perfect. No crack and void were found at the interface. The heat-affected zone in the Ti substrate exhibited typical martensite morphology of quenched microstructure. Compared with B4C cladding coating, the B4C+10wt%Ti cladding coating had a finer microstructure and higher content of TiB phase and lower content of the TiB2 phase.