Abstract: On the basis of study on generalized pose and the theorem that rotation transformation from the base coor-dinate to an arbitrary one can be described as a single equivalent rotation about a given rotational axis,it isproposed that the orientation of robot can be described by using the vector of equivalent angular displace-ment.The concept of pose motor and its Plücker linear coordinate are established and used to describe the po-sition and orientation of robot.Based on the fact that there is a one-to-one correspondence between the ori-ented straight lines in three-dimensional dual space,the interpolation plannings corresponding to the posemotors are developed in dual space.A new method of robot CP motion analysis and trajectory planning is pre-sented.The correctness of the theory and derivation is confirmed by an example.