Abstract: The present paper deals with the genus Paeonia in Xinjiang, whose taxonomy has been confused. Based on the field observation, population sampling and the examination of herbarium specimens, a taxonomical revision is made in this paper. Two species are recognized, i. e. Paeonia anomala L. and P. sinjiangensis K. Y. Pan. P. altaica K. M. Dai et T. H. Ying is reduced to P. sinjiangensis and P. hybrida (= P. anomala var. intermedia) is reduced to P. anomala. The diagnostic characters of the two species are described and illustrated, and a map of their distribution in Xinjiang is presented. A key to these two species is provided here. 1. Roots straight, not thickened; sepals all caudate, less frequently one or very rarely two non-caudate ................................................ 1. P. sinjiangensis K. Y. Pan. 2. Roots fusiform or tuberous; inner three sepals non-caudate, less frequently one of them caudate .............................................................. 2. P. anomala L. key words Xinjiang; Paeonia; P. anomala; P. sinjiangensis; revision