On the basis of three mountain sites (Mount Tai, Hua and Huang) newly founded in east-central China and several other sites from the Acid Deposition Monitoring Network in east Asia (EANET) and WMO World Data Centre for Greenhouse Gases (WDCGG), we investigate seasonal cycle of ozone over east Asia and its budgets in east-central China by using a regional chemical transport model (NAQPMS). The observations show a striking ozone pattern of two sharp peaks in May-June and September–October at three mountain sites in east-central China which are higher than those observed at other mountain sites in Europe and North America. Ozone budgets analysis by the model confirms that maximum of net photochemical productions reaches 31.8, 15.1, and 11.4 ppbv/d at Mount Tai, Hua, and Huang, respectively. The net photochemical production dominates the formation of ozone maximums at Mount Tai and Hua in June, and the importing transport also plays a comparable importance at Mount Huang. In comparison with those in the western North Pacific, east-central China shows stronger net photochemical productions, which are comparable to anthropogenic sources regions in Europe and North America.