Abstract: In order to satisfy demands of rapid, accurate, automatic detection of mine-used wind speed sensor and wind speed impact test of mine-used gas sensor, an automatic control system of circular low speed wind tunnel was designed. The system uses PLC as main control unit, and adopts PID control module to control frequency converter fastly according to relationship between wind speed and static pressure difference and through automatic collection and calculation of atmospheric pressure, wind temperature, static pressure difference, so as to realize automatic output of wind speed by controlling change of rotate speed of motor. The uncertainty evaluation was analyzed including uniformity, stability and turbulence intensity of pitot tube, automatic control system, wind tunnel wind speed in the measuring process for detecting GFY15 mine-used wind speed sensor as example.The evaluation results show that the automatic control system can meet needs of automatic detection for mine-used wind speed sensor.