Abstract: In view of problems of low illumination, a lot of dust and complex electromagnetic environment in coal mine underground, and images' quality captured by underground monitoring equipment would be reduced in transferring process caused by underground noises, an underground monitoring image sharpening device based on embedded system was designed. The device uses wavelet threshold algorithm and DSP embedded system, and it can effectively restrain noise, meanwhile keep details characteristics and peak point of original images, which greatly enhances monitoring image clarity.