Abstract: A specimen collected from the Early Cretaceous Yixian Formation, Jehol Group of Liaoning, China, represents a new genus and species of maniraptoran theropod. It comprises almost complete articulated pectoral girdles, forelimbs and some ribs and is here named Yixianosaurus longimanus gen. et sp. nov. Diagnostic features of the new species include manus 140 % as long as humerus, manual phalanx Ⅱ-2 longer than metacarpal Ⅱ, manual phalanx Ⅲ-3 244 % as long as phalanx Ⅲ-1, and manual phalanx Ⅲ-2 bearing a proximoventral heel. With the integuments preserved on the holotype specimen, Y. longimanus represents the ninth feathered dinosaur species reported from western Liaoning. The elongated penultimate phalanges of Y. longimanus indicate an improved grasping capability and might represent an adaptation to the arboreal habit. The discovery of Y. longimanus increases the diversity of theropod dinosaurs in the Jehol Fauna.