A computer-controlled micro-motion analyzer(MMA) to study the dynamic behavior of movable structures of microelectromech-anical systems(MEMS) is introduced.It employs two optical nondestructive methods:computer microvision for in-plane motion measurement and phase-shifting interferometry for out-of-plane motion mesasurement.This fully integrated system includes a high performance imaging system,drive electronics,data acquisition and analysis software.This system can freeze the fast motions of MEMS devices by using strobed illumination,and it can measure the motions in 3-dimensions at frequencies from 1 Hz to 10 MHz with nanometer resolution.The capabilities of this system are illustrated with a study of the dynamic behavior of a surface micromachined polysilicon micro-resonator.