Laser beam welding was used to join SiCp/6063Al composite and Ti was used as in-situ material. The result showed that weld and HAZ are narrow and no pore can be found in weld. The analysis on microstructure of weld center showed that the grain size of weld matrix is very fine and the grains crystallize as equiax crystal, microstructure of weld is very compact and no obvious micro - gaspore and crack are found. No needlelike reaction product A14C3 is observed in weld, which can produce when SiC particles react with matrix during fusion welding. There are many finer TiC particles which are nearly round and the distribution of the particles is even in weld. The whole welding zone turns to be as follow: the base metal is SiC particles reinforced Al matrix composite and the weld is partial zone in which TiC particles are reinforcement and Ti is matrix. The result showed that A14C3 in weld center is restrained completely with Ti as in - situ' weld - alloying materials during impulsed laser beam welding for SiCp/6063 composition and the intensity of jiont is increased due to rapidly solidified phase such as TiC.