Abstract: Based on the method of molecular dynamics， a numerical model was presented to simulate the behavior of such a ellipsoid experiencing optically induced dielectrophoresis (ODEP). The ODEP and Stokes force exerted on the ellipsoid were studied， and the Runge-Kutta method was used to calculate the self-rotation speed regarding different aspect ratio of ellipsoid. The electric field was solved by using COMSOL software， and the trajectory of the ellipsoid experiencing ODEP was simulated on the basis of the Velocity-Verlet algorithm. The simulation results indicated that the greater particle aspect ratio， the faster the speed. The ellipsoid at 28， 30μm location was controlled by the positive ODEP， which could move towards the light pattern along the gradient of the electric field magnitude， and the maximum speed could reach 312μm/s. The simulations results of the rotation speed and the trajectory are consistent with those in the experiment.

Key words: optically induced dielectrophoresis, optoelectronic tweezer, Runge-Kutta method, Velocity-Verlet method, ellipsoid