Abstract: A new type of piezoelectric-electrorheologica linear stepper motor studied by us is elucidated in this paper. With improving of electrorheological fluid clamper (ER clamper) of the motor, the moving speed of the motor were increased from 0.12 mm/min to 1.8 mm/min with high resolution of 0.1 μm and with driving force of 100 gf. The experimental results show that prototype of motor with computer control system has excellent control properties and good position precision with large travel range.