During the recent decade, the active noise control technology has becoming a hotspot of the noise controlling field, which is the extend and intercross of several subjects. Its ability of eliminating low frequency noise, light weight and compactness have been fully understood Firstly this paper simply introduce its theory. Then the actuality and nodus of its theory research, implementation technique and product at home and abroad are elaborated in full. Finally some problem of its practicability are analyzed further and several major developing directions are presented.