The utility model relates to a pipe inner wall distraction device, include: wear to establish the tensile axle of body hole, tensile axle extends the second section of setting including the first section that stretches into the body hole with by first section one end outward to the body hole, is formed with to push away on the lateral wall of first section and draws the face axially movable, pushes away to draw the face and keep away from second section one end side direction and lean out, setting supporting on second section outer lane is leaned on, the support piece in second section outer lane is established to axially movable ground cover, and support piece is close to first section one end, telescopically sets up and is supporting the drive arrangement who leans on between piece and the support piece, and with push away the opening mechanism that props who draws a sliding fit. The utility model provides a distraction device utilizes the flexible outer axial displacement of tensile axial hole that drives of drive arrangement for propping opening mechanism and pushing away relatively and draw the face and slide, radial removes and removes to extrude the hole lateral wall, makes the body strut the deformation, and operation process is simple, prevents that the bolt of balancing weight from droing, improves balancing weight life.