The bulk acoustic wave (BAW) sensors are developed rapidly in recent ten years, for which have high sensitivity, quasi digital output, integrality and high operating frequencies. Due to the characteristic of high operating frequency, the readout circuit of the BAW sensor is complex and not easy to be integrated, which leads to the result that BAW sensors haven′t been used in our life. In order to promote the practicality of BAW sensors, an original idea that uses a sixport reflectometerbased readout circuit of BAW sensor instead of the vector network analyzer is proposed in this work. The feasibility of the sixport reflectometerbased readout circuit of BAW sensor has been verified by using the RF simulation software (Advanced Design System) of Agilent company, and a circuit design scheme of the sixport network which is required by the radio frequency output signal detection of FBAR is given.