Pachyserica sunfengyii is a species of beetle of the family Scarabaeidae. It is found in China (Guangxi).
Adults reach a length of about 11 mm. They have a dark brown, oval and strongly convex body. The dorsal surface has a strongly greenish, iridescent shine. The elytra are without dark spots and the antennae are yellow. The dorsal and ventral surface have fine, partly patchily distributed, or dense, short, yellow, scale-like setae. There are a few long, fine, erect, yellow setae on the head, pronotum and anterior elytra.
The species is named after its collector, Mr. Feng-Yi Sun.