This paper investigates an optimal design of a double-sided slotted iron core type permanent magnet linear synchronous motor (PMLSM) using for ropeless elevator system. To obtain the optimal structure, the combination of response surface methodology (RSM) and two dimensional (2D) finite element analysis (FEA), which can solve the problem effectively without much time consuming, is utilized to investigate the PMLSM characteristics. Moreover, the detent force is more detailed analyzed with the manufacturing consideration. In final some numerical calculation results are reported to validate the applicability of this double-sided slotted iron core type PMLSM in ropeless elevator system. Introduction