Abstract: For the problems of low measurement accuracy, poor stability, and frequent maintenance of dust concentration detection equipment in coal mine, a model for the decay and fluctuation of C14 atomic nuclei is established and the corresponding detection data processing method is proposed based on the analysis of the principle of β-ray absorption. Based on the design of gas pretreatment device and PID constant current control technology, the overall design of dust concentration detection device by ray absorption method is finally completed. The experimental results show that the relative errors of the sample machine and the manual sampling weighing method are both lower than ±10%, which can meet the detection requirements of dust concentration in underground coal mines.