Abstract: In this paper,YAG laser pulsed MIG arc hybrid welding process for aluminum alloy has been studied.A welding head for YAG laser pulsed MIG arc hybrid welding has been designed and manufactured,which was mounted on an arc welding robot.In order to find out the optimum welding parameters,the effects of YAG laser power and defocusing distance,the distance between laser beam and arc center,the welding speed and arc current,as well as AC/DC pulse arc on the weld bead formation have been investigated.By means of a high speed video camera,the behavior of pulsed arc and laser induced plasma plume were observed.The experiment results showed that in a wide range of parameters with YAG laser pulsed MIG arc hybrid welding for aluminum alloy,the weld formation was very sound.The weld penetration was increased by more than 4 times compared with YAG laser only,and the welding speed was obviously increased compared with MIG only.It has been proved that the YAG laser pulsed MIG arc hybrid welding for aluminum alloy is a perfect process.