Acer yangbiense Y. S. Chen & Q. E. Yang, a new species from Yangbi County, Yunnan Province, is described and illustrated. This species is similar to Acer leipoense Fang & Soong from western Sichuan in having a pale gray abaxial surface of the leaves, a much longer glabrous infructescence and fruiting pedicels, and convex nutlets, but differs by its larger 5-lobed leaves with a cordate base, abaxially densely pubescent veins and veinlets, and pubescent young branchlets and petioles.