The invention discloses a portable automatic spot welding robot. The portable automatic spot welding robot structurally comprises a welding head workbench, an electric control cabinet, a driving cable, a moving rail, soldering iron, a placing groove, a mounting base plate, a workbench, a tin recovery box, a supporting column, a touch screen, a tin guide pipe and a tin feeding box. The portable automatic spot welding robot has the advantages that in order to realize more accurate spot welding operation, a lifting driving mechanism is arranged on the workbench, equipment required to be welded isplaced on the position, the equipment cannot be started under the condition that the equipment is placed in a misplaced mode, the phenomenon that the welding effect is affected due to the fact that the equipment is deviated in the welding process can be avoided, a pin mechanism is arranged so that accurate tin feeding can be realized, the situation that tin materials are wasted due to the fact that the tin materials are accumulated and block a channel in the conveying process can be avoided, and therefore efficient and accurate welding can be realized, and meanwhile, the environmental protection and conservation effects can be achieved.