The invention discloses a double-section type exhaust pipe welding device capable of carrying out leakage detection on an exhaust pipe. The double-section type exhaust pipe welding device comprises abottom plate, a clamping mechanism, a sliding rail, a welding mechanism and a movable sleeve, wherein a movable rail is installed on one side of the top of the bottom plate, a machine cabinet is fixedto one side of the top of the bottom plate, a servo motor is installed on the side, away from the machine cabinet, in the movable rail, and a lead screw is installed at the output end of the servo motor. According to the double-section type exhaust pipe welding device capable of conducting leakage detection on the exhaust pipe, through arrangement of an air pump and an ultrasonic air leakage detector, the air pump can blow air to the welded exhaust pipe, the ultrasonic air leakage detector can surround a welding part to detect air pressure leakage and welding sealing performance of the welding part, and meanwhile intelligently position an air leakage position, the welding mechanism can conduct and secondary repair welding work on the air leakage position in time, so that time and labor are saved, the integration degree is high, and the welding quality is higher.