The principle of magnetron sputtering is introduced and the balanced and unbalanced magnetrons are compared and the necessity of unbalanced magnetrons is explained as well. Several recent developments in plasma magnetron sputtering, i.e., unbalanced magnetron sputtering, pulsed magnetron sputtering and ion assisted sputtering, are discussed. The recent developments of unbalanced magnetron systems and their incorporation with ion sources result in an understanding in growing importance of the magnetron sputtering technology, which makes the technology an applicable deposition process for a variety of important films, such as wear-resistant films and decorative films.