The laser beam with pre-gasification pulse is used in titanium Ti6Al4V laser spot weld bonding test. The influence of residual carbon from adhesive pyrolysis on microstructure and properties of titanium laser spot weld-bonded joint is studied. The results show that lots of TiC appear in the titanium weld-bonded joint because of residual carbon from adhesive pyrolysis, and interface reaction zone compose mainly by TiC appear in the interface between spot-welded joint and adhesive layer. The residual carbon that affects the microstructure of titanium laser spot weld-bonded joint is mainly from the pyrolysis in the pre-gasification pulse, and the residual carbon which composes interface reaction zone is from the back flow of adhesive after the joining process. The advent of TiC increase the hardness of titanium weld-bonded joint, but also has an adverse effect on the tensile-shear load of titanium weld-bonded joint.