Positive pressure sampling tube

The utility model discloses a positive pressure sampling tube, which relates to the technical field of sampling equipment and comprises an outer tube, one end of the outer tube is provided with an outer tube sealing cover, the outer tube sealing cover is provided with a liquid outlet hole, a first piston is slidably mounted in the outer tube, and the first piston, the outer tube and the outer tube sealing cover form a liquid storage cavity; a push rod assembly for controlling the first piston to compress the liquid storage cavity is mounted on the outer pipe, and an air compression cavity for resetting the push rod assembly is further mounted on the outer pipe; by arranging the air compression cavity, when the first piston slides towards one side of the outer pipe sealing cover in the outer pipe, the second piston synchronously compresses air in the air compression cavity, so that the first piston has an automatic rebounding function, the structure is simple, the design is reasonable, a reset spring does not