In this paper, we describe the design and fabrication of a microfluidic device for cell lysis and DNA purification, and the results of device tests using a real sample of buccal cells. Cell lysis was thermally executed for two minutes at 80 degrees C in a serpentine type microreactor (20 microL) using an Au microheater with a microsensor. The DNA was then mixed with other residual products and purified by a new filtration process involving micropillars and 50-80 microm microbeads. The entire process of sample loading, cell lysis, DNA purification, and sample extraction was successfully completed in the microchip within five minutes. Sample preparation within the microchip was verified by performing a SY158 gene PCR analysis and gel electrophoresis on the products obtained from the chip. The new purification method enhanced DNA purity from 0.93 to 1.62 after purification.