A micro-scale Fluorescence Activated Cell Sorter(μ FACS) for biomedical research and clinical dignostics is under development . In this thesis, we present a novel microfluidic device to separated beads with various fluorescence intensities. There are three parts of our system: focusing, detection and separation..This system is designed to allow counts and sorting of cells that have fluorescent characteristics. Fluorescent beads were injected into the microfluidic chip and focused to the center of the channel by the hydronamic sheath flow. Also, fluorescent beads were excited by a 532㎚ laser at 30㎚ and concurrently detected by a photomultiplier tube(PMT). According to their fluorescence intensities, beads were separated into three outlets by a dielectrophoretic(DEP) force. Compared with conventional FACS, our integrated cell sorter has better capabilities for detecting fluorescence beads and cells.