In this paper,a novel optical sorting method is developed by utilizing the evanescent wave in an optofluidic waveguide.Two different laminar liquid flows are injected into an optofluidic channel to form a liquid-liquid interface.Evanescent wave is generated due to the total internal reflection by applying an illumination light at a critical angle [1-2].Three micro- particles inside the field with different sizes and refractive indices can be quickly sorted by controlling the flow rate and the laser power.Figure 1 illustrates the working principle of the optical force in an optofluidic channel for micro-spheres sorting.This channel consists of two laminar flows with a larger refractive index in the down-stream.Micro-spheres are injected into the up-stream,and can be manipulated by the evanescent wave from the interface.Figure 2 presents the simulation results of different flow mixes in the micro-channels.Various velocity profiles can be obtained by controlling the flow rate and different fluids Figure 3 illustrates the theoretical calculation of the optical force on micro-spheres with different diameters by controlling the penetration depth.The optical force in this case can be powerful enough to conquer the drag force exerted by the flow,resulting the "pulling back" effect.Figure 4 shows the experimental results of trajectories of micro spheres resulting from the optical force.Fig.4a & b indicate that laser power of 20 mW is unable to move the spheres with a diameter of 1μm,whereas 80 mW can sort them efficiently.Fig.4c & d show large particles are pulled back by optical force.In conclusion,an optofluidic device for micro-spheres sorting by using optical force combined with the hydrodynamic focusing is demonstrated.