Disclosed are a device and a method for synchronizing electric arc welding fusion depth information and welding data collection information. The device for synchronizing the electric arc welding fusion depth information and the welding data collection information is composed of a welding cabinet, a scriber, an electromagnetic valve, an air pump, a controller and a scribe board, wherein the scriber is formed by sequentially connecting an air cylinder, a scribing needle fixture and a scribing needle from top to bottom, the air cylinder is fixedly connected with the welding cabinet, and the air pump, the electromagnetic valve and the air cylinder are connected into an air circuit through air pipes. The method for synchronizing the electric arc welding fusion depth information and the welding data collection information includes steps: inputting a control signal of a controller into a control end of the electromagnetic valve so as to achieve air circuit switching, change of moving directions of the scribing needle and control of scratches on the scribe board, generated by the scribing needle; confirming data collection starting and ending positions on a work piece through marks on the scribe board after welding, cutting, polishing and eroding the work piece on a position of the maximum fusion depth along the welding direction, identifying a fusion line and performing fitting, and thereby generating the fusion depth information synchronous with the collection data. The device and the method for synchronizing the electric arc welding fusion depth information and the welding data collection information are used for rapidly measuring the welding fusion depth information offline and synchronizing the welding fusion depth information with the welding data collection information, and thereby can facilitate modeling and control studies, which are related to the fusion depth.