An automatic material changing and welding system for stamping materials includes a welding transfer sliding table and a welding platform. The automatic material changing device further includes a feeding system. The feeding system includes a double-head uncoiling machine, an automatic feeding machine and a flattening machine. The automatic material changing device is used for automatic feeding for a stamping machine. The system triggers a material changing signal through a sensor to control and integrate the welding transfer sliding table and the welding platform to act to execute a welding procedure, so that the stamping materials are in welding connection with new and old coiled materials through a welding connection plate to realize continuous production operation of an automated stamping production line.