Thanks to the freedom of the press for decades, Taiwan has always been a battlefield of general magazines. The market competition is quite intense. This study adopts the niche theory of organizational ecology as a theorectical farmework, and analyzes the niche competition among China Times Weekly, Next Magazine, and Mirror Magazine. Methodologically, 42 issues were selected from the three magazines from 1997 to 2017 for content analysis of news and advertisement. Three main conclusions were drawn: (1) China Times Weekly is a generalist, while Mirror Magazine is a specialist; (2) The competition between China Times Weekly and Next Magazine is the most intense; (3) China Times Weekly has competitive advantage in news, while Next Magazine has competitive advantage in advertisement.