For robotic endoscope, some researchers suggest pneumatic actuators based on inchworm motion. But, the existing endoscopes are not seemed to be replaced completely because human intestine is very sensitive and susceptible to damage. We design and test a new locomotion of robotic endoscope able to maneuver safely in the human intestine. The actuating mechanism is composed of two solenoids at each side and a single permanent magnet. When the current direction is reversed, repulsive force and attractive at the opposition side propels permanent magnet. Impact force against robotic endoscope transfer momentum from moving magnet to endoscope capsule. The direction and moving speed of the actuator can be controlled by adjusting impact force. Modeling and simulation experiments are carried out to predict the performance of the actuator. Simulation experiments show that force profile of permanent magnet is the dominant factor for the characteristic of the actuator. The results of simulations are verified by comparing with the experimental results.