Abstract: A new species of the genus Aconitum (Ranunculaceae),Aconitum rotundocas-sideum,is described here from Shaanxi Province.Having similar habit and galeiform upper sepals,this species is closely related to A.crassicaule W.T.Wang endemic to Gongshan County,Yunnan Province,though the latter differs by its flower arrangement in a panicle with three small 3-flowered racemes,usually arcuate pedicels,smaller rounded-galeiform or subglobose,conspicuously nerved,not beaked upper sepal and smaller lateral sepals, and 2-denticulate stamen filaments.