Expansion pipe joint structure

The utility model relates to an expansion pipe joint structure which is mainly composed of an inner body, an outer body, a rotating ring, a clamping ring and two leakproof rings, wherein, the inner body is a hollow barrel body, the front end of the inner body is provided with a fixed disk, and a lateral margin of a tail end is provided with ring grooves for plugging the two leakproof rings. The outer body is also a hollow barrel body, the tail end is provided with the fixed disk, and the periphery of the front end is provided with outer screw threads. The rotating ring which is sheathed on the inner body can be screwed on the outer body through the outer screw threads. When the rotating ring is tightly screwed with the outer body, the inner body which is plugged at the inner margin of the outer body is pressed, and forms a state of smoothing moving without falling off.