In this work,we developed a new technology by the combination of microfluidic device with mass spectrometry for the study of drug metabolism.The microfluidic device contains two different functional units: (1) a circular cell culture chamber; (2) a micro-solid phase extraction channel for sample cleanup and concentration prior to mass analysis.By connecting the two separated microchannels with polyethylene tubes,drug metabolism studies related to functional units,containing cell culture,metabolism generation,sample pretreatment and detection were all integrated into a microfluidic device.