Modal analysis is a technology for vibration characteristic research. It is the foundation for structural dynamics analysis. Natural frequency is a very important performance in dynamics analysis. Modal characteristics of the Permanent Magnet Linear Synchronous Motor (PMLSM) for ropeless elevator were investigated by finite element method (FEM). FEM models for modal analysis were built for the primary winding, iron core, fixed block, secondary back iron and permanent block by appropriate structure simplification. The influences on natural frequencies of the PMLSM were analyzed. Natural frequencies and mode shapes were simulated by FEM. The accuracy of the FEM analysis is validated by the modal analysis experiment of hammering method. KEY WORDS: ropless elevator; PMLSM; modal analysis; FEM; natural frequency Ⅰ. INTRODUCTIONCompared with the traditional hoisting system, the ropeless elevator droved by PMLSM is promising. Its main feature is high efficiency, small space, and high security [1] . The ropeless elevator is droved by PMLSM guided by two or more rail，and the rails ensure the directionality of its running and horizontal stability, Whether it is unilateral open-or bilateral closed, the air gap between the primary and secondary of PMLSM will seriously affect the normal force between the mover and the stator, and this would inevitably lead to changes in the system dynamics. During operation, vibration and friction force caused by intrinsic thrust and normal force fluctuations between the primary and secondary of PMLSM seriously affect the dynamic performance of the system, resulting in PMLSM fatigue and shorten its life. In order to improve the density of PMLSM thrust and reduce thrust and normal force fluctuations, the PMLSM for ropeless elevator taking the high density, wide speed, lightweight and low-cost designs, this leads more complicated in structure, lighter in weight and thinner in thickness of PMLSM, all of this result in difficult to increase the stiffness and suppressed the electromagnetic vibration of PMLSM [2] .