Abstract: The 3-roll Planetary Cross Mill developed in the middle of 1970’s is a new type mill with huge reduction and high efficiency. It provides an economical method for rolling semifinished and finished rounds. For roughing process of wire, tube blank and light section, this mill can get through the same reduction in a single pass as would be done by 7-8 stands in a conventional roughing line. Consequently, it is found very advantageous to replace the conventional roughing train in an existing bar or light section plant with a planetary cross mill in consideration of higher productivity, less energy consumption, better product quality, and higher level of automatization. Relevant factors such as kinematics, construction, and determination of characteristic parameter and rolling force and so on have been calculated theoretically with a view to establishing a suitable design.