In this paper, a study of process monitoring technology for the laser hybrid welding was conducted. The laser welding, arc welding and the industrial robotic systems were used with robot-based laser hybrid welding systems. The laser source, arc welding and robot systems are used to increase the processing speed and to improve the efficiency of welding processes. The robot-based laser hybrid welding system was equipped with a laser head and arc welding gun for laser hybrid welding. The welding joints of steel plate and aluminum plate were butt and Fillet joints. The quality testing of the laser hybrid welding was conducted by observing the shape of the beads on the plate and the cross-section of the welded parts, analyzing the results of mechanical tensile test, and monitoring the plasma intensity by using UV and IR sensor. This paper proposes the quality monitoring method and the robot-based laser hybrid welding system as a means of resolving the limited welding speed and accuracy of conventional laser welding systems.