Abstract: The paper covers main aspects of the 11-roll straightener for hi precision tubular products and the complex roll-framed straightener developed by Xi'an Heavy-duty Machinery Research Institute, including structure, arrangement, working principles, mill type and parameters as well as operaions of the mills by demostic customers. Relevant operatoinal practices show that the newly developed straighteners have such advantages as compact, logic structure, high straightening accuracy, suitability for straightening of a great variety of materials and satisfactory production performances. The said 11-roll straigntener for hi precision tubular products has been invention patented.