Abstract: In view of problems of expensive and inconvenient to wear of existing active anti-noise earmuffs, an active anti-noise earmuff in heavy noise environment was designed. The earmuff takes TMS320VC5509 as processor, and adopts adaptive noise cancellation method and the normalized least mean square algorithm to enhance adaptive noise cancellation performance. Combined with passive noise reduction technology, the earmuff realizes purpose of noise cancellation in heavy noise environment. The experimental results show that anti-noise performance of the earmuffs is up to 30 dB.