This paper presents a design analysis of an inchworm motor for applications requiring high force and large displacement with fine resolution. The piezoelectric inchworm motors are inspired from the motion features of nature inchworm. The motor can achieve a long range motion by repeating a clamp-extend-clamp cycle as a nature inchworm. The motor consists of an extending mechanism and two clamping devices. The clamping device is designed in order to obtain high clamping forces with the rail, while the extending mechanism is designed for a large displacement and high force using multi-stack piezoelectric actuators. The detailed design of the inchworm motor was performed using finite element analysis.