This paper is an attempt to investigate, through numerical simulation and optimization methods, the optimal design of dielectrophoretic (DEP) ctyosorters under certain constrains. DEP electrodes is designed to maximize the sorting resolution of a cytosorter, defined as the degree of (bio)particle deflection. In order to obtain the maximal particle deflection, different non-uniform electrical fields are produced by combinations of electrodes with different lengths. The findings of numerical simulation indicate that the design of electrodes near Xf/L= 0.283 and Xb/L=0.25 can maximize the particle deflection in the current flow sorter design constraints. In this study, an optimization method to accelerate the cytosorter design process is also presented. By using the numerical simulation and the optimization method, the cases for optimal design processes can reduce from 465 to 50 and still get a reasonable result.