This paper investigates an optimal design of a double-sided iron core type permanent magnet linear synchronous motor (PMLSM) for ropeless elevator system using response surface methodology (RSM). An inherent drawback of the PMLSM is the detent force that will generate the pulsations of the propulsion force, deteriorate the smoothness of motion drive, and make passengers feel nervous. To solve the force pulsations the combination of two dimensional (2D) finite element analysis (FEA) and RSM is utilized, which can solve the problem effectively without much time consuming. The validity and effectiveness are verified by some numerical calculations.