A new penaeoid shrimp collected from the Middle Triassic Member II of the Guanling Formation in the vicinity of the city of Luxi, Yunnan, southwest China, is a new species, Aeger luxii n. sp. The new species possesses prominent spinose third maxillipeds, which is one of the typical characteristics of Aeger. The new species differs from the type species, Aeger tipularius from the Jurassic Solnhofen Plattenkalk, in having a long, smooth rostrum with no subrostral spines. The new taxon increases the diversity of Chinese decapods, and further expands our knowledge of the phylogeny and evolution of the Mesozoic decapods. The find is the first complete specimen of Aeger in the Middle Triassic, and reveals a close biogeographic connection of the marine ecosystem between Eastern and Western Tethys.