Abstract: For the problem that traditional optical methods for measuring dust concentration were susceptible to environmental temperature, light source and photoelectric device, a dust concentration measuring method using infrared difference method was proposed, and a dust concentration measuring device was designed which was based on the method. The device calculates dust concentration by a data acquisition and processing module which takes S3C2440 as a core and based on infrared differential measuring principle, and uses wavelet threshold denoising method to process the acquired signals by LabVIEW signal processing module. The debugging result shows that the device is high in signal acquisition precision and measurement accuracy of dust concentration.