Dielectrophoretic Field-Flow Fractionation (DEP-FFF) is a technique that selects particles of interest from a mixture of many samples.DEP-FFF technique firstly used DEP force to levitate particles to different heights according to their dielectric properties.Levitated particles are then separated by their velocity difference in a microchannel, as shown in Figure 1.By balancing DEP forces with the gravitational forces, one can obtain the analytical solution, as well as its approximate solution, for the particle levitation heights.In the mean time, numerical simulation is carried out in Figure 2.The simulation results are compared with the analytical and approximate solutions in Figure 3.