The utility model relates to a telescopic tube, wherein, an inner tube is fixedly arranged on a fixing seat of the inner tube. An outer tube is fixedly arranged on a fixing seat of the outer tube. The fixing seat of the outer tube is fixedly arranged on a base. A polygonal column upwards penetrates through and extends out of the base. The polygonal column can penetrates through a linkage seat. An eccentric wheel is sheathed on an eccentric position on the linkage seat. The fixing seat of the inner tube is fixedly arranged on the linkage seat. After the inner tube is extended and adjusted to a proper length relative to the outer tube, the base is rotated to lead the base to be linked with the polygonal column, and the linkage seat is led to rotate. Then, the inner lateral wall surface of the outer tube can be clamped by the eccentric wheel on the linkage seat, and the linkage seat can be positioned.