Waste gas sampling device

The utility model discloses a waste gas sampling device and relates to the technical field of waste gas sampling. The sampling device comprises a conversion tube and a sampling tube, the sampling tube comprises a tube body and a connecting tube connected with one end of the tube body, a piston is arranged in the tube body and connected with a pull rod, internal threads are arranged on the inner wall of the end, away from the connecting tube, of the tube body, and the internal threads of the connecting tube are matched with a threaded cylinder. According to the exhaust gas sampling device, the sampling pipe is firstly held in a hand to face the scales, then the threaded cylinder is rotated to enable the end, close to the piston, of the threaded cylinder to reach the preset corresponding air exhaust scale position, then the connecting pipe is connected with the conversion pipe, and then the first valve is opened to drive the piston to slide to extract exhaust gas by pulling the pull rod; when the sampling pipe