The invention discloses a motor vertical swing arm module of a three-in-one welding trolley. The motor vertical swing arm module comprises a telescopic arm installed on a trolley body; a vertical motor and a gear box are arranged on the telescopic arm; the motor is connected with the gear box; and a welding gun clamp located on one side of the motor is further arranged on the telescopic arm. The distance between the motor and a heat source reaches 200MM, the motor is not directly irradiated by heat radiation, the module is heated from a face to a point, the heating face is reduced, and long-time continuous welding is met. After the swing arm module is assembled, debugging is conducted according to corresponding welding parameters, the swing direction, the telescopic distance and the like are adjusted, and the welding operation requirement is met. The problem that due to continuous welding, three-in-one trolley parts are overheated, and swing arms fail is avoided, the effect is good, a welding machine works stably, the welding quality is stable, the overheating shutdown phenomenon does not occur after high-strength use, and the manual reworking situation is correspondingly avoided.