Abstract: Addressing the shortcomings staying with the rotary-rolling pipe mill such as rather long rolling cycle and low output,a new type dual-mandrel-retaining system is designed.Described in the paper are the main aspects of the said system,including the structural composition,the advantage analysis and the actual application result,etc.It is regarded via the analysis that employment of the said system which gets one mandrel being used for rolling,while the other being pre-piercing the shell shall bring about such advantages as real-time control of the mandrel,shortening the mandrel circulation time,enhancing the rolling cycle,increasing the mandrel service span,increasing pipe output and yield,and reducing the production costs.