Abstract: In the article the three types of roll stand changeover of the 3-roll mandrel mill are described,and the roll changeover movement procedure is analyzed.The structure of the roll-stand changeover device of the said pipe mill is studied.As a result it is concluded that three roll-stand changeover types for the 3-roll mandrel mill are currently adopted,i.e.,the axial changeover,the lateral changeover and the bilateral changeover,among which the axial changeover takes relatively rather long time;and that the three key aspects related to enhancing roll-changing efficiency so as to realize fast roll-changing operation are control of the drive spindle engagement,driving-back of the drive spindle,and the device-inplace detection.