Abstract: Ulmus mianzhuensis Yi et L. Yang, a new species of Ulmaceae from Sichuan,China, is described and illustrated. The new species is similar to U. parvifolia Jacq. in having pale pubescent at stigma of samara,the lateral wing of samara more narrow than stone,the stone sits at samara near emarginate of the top, but differs by having darkgrey and irregularly squamosely shallowly dehiscing bark, lamina acuminate in top, perianth splitting to base and persisting, margin upwards ciliolate, samara narrow elliptic, center broadest, with pedicel equalling the perianth (about 2 mm long), peduncle about 1 mm long.

Key words: Ulmus, U. mianzhuensis Yi et L. Yang, new species, Sichuan, China