Based on the principle of infrared absorption,a novel design of infrared sensor measuring the dust concentration is proposed in the paper.The linear mathematical model of sensor is established based on Lambert-Beer,the structure of double light paths and applying difference algorithm.Msp430f149,ICL7605 and AD620 are applied in the signal processing section.Then,the reliability of the measurement is verified by experimental data.It seems that the proposed infrared absorption dust sensor can not only improve the measurement accuracy of the sensor but also offer an interesting and significant solution for the safety monitoring in the coal mine and flue.