The invention discloses an open-type three-jaw self-centering rotation device. The device comprises a self-centering clamping disc portion and a self-centering rotation portion which are assembled together. The self-centering clamping disc portion is used for clamping workpieces. The self-centering rotation portion drives the workpieces to conduct rotation machining. The open-type self-centering clamping disc is adopted, so that the open-type three-jaw self-centering rotation device is particularly suitable for automatic bottoming welding of flanges and connecting pipes with the flanges on the two edges, and the workpieces can be directly lifted away along an opening of the clamping disc after welding is completed. The open-type three-jaw self-centering rotation device is quite suitable for automatic welding, hole forming, cutting and the like of some long circular workpieces, the working mode that long workpieces must be inserted into one end of rotation clamping disc equipment with a central through hole during operation is avoided, the long workpieces can be directly placed on the open-type three-jaw self-centering rotation device from bottom to top by the adoption of the open-type three-jaw self-centering rotation device, unnecessary man-hour waste can be reduced, the working efficiency of the open-type three-jaw self-centering rotation device is improved, and the overall length of the open-type three-jaw self-centering rotation device is decreased.