Abstract: In this paper，the complex interplolation method ( CIM) is proposed for analysis of the planar motion

of rigid bodies. Based on the known kinematical information ( displacement，velocity and acceleration) of two

points in a rigid body，the displacement，velocity and acceleration of any other point in the rigid body can be determined

by the CIM.The present method provides a unified way to the analyses of displacement，velocity and acceleration

of the planar motion of a rigid body，on the other hand，it is easy to implement in the computer.

Key words: planar motion of rigid body, velocity analysis, acceleration analysis, complex interpolation method