Abstract: This paper addresses the feasibility of visual sensing and real time control of weld pool dynamics in pulsed GMAW. Because of the complexity of fuse dripping transition in pulsed GMAW,it is simulated for welder to observe weling pool changes and regulate weld parameter for control of weld seam figuration.The visual sensing system was established for monitoring welding pool variety. The fuse dripping transition influences on the weld pool size were considered as black box process for simplifying complexity,and using arc spectrum distribution of pulsed GMAW and image processing for picking up weld pool characters,the real time detecting of weld pool dynamics in pulsed GMAW was realized. The model of weld pool dynamical process was be presented in this paper by identification algorithm,and then the PID controller was designed for real-time control of weld bead width during pulsed GMAW. The experments show that the real time and precision requirements for detecting and control of weld pool changes and bead width of puled GMAW could be satisfied by developed image processing and control algorighm on the established systems.