Abstract: The late Mr. Liu Zhicheng (1982) established a new leptolepid-level fish— Longdeichthys luoiiaxiaensis, based on the specimens from the "Upper Jurassic" of Ningxia (V2333) and Nei Mongol (2334), and considered that this genus belongs to the family Leptolepidae. During the field works in 1990—1991, we have collected a large number of specimens of Longdeichthys from the Jiufotang Formation of Yixian, Chaoyang and Heishan of Liaoning Province (Northeastern China), of which the materials from Boluochi of Chaoyang are detached and scattered bones, partially well preserved, and concurrent with the early birds —Cathayornis Zhou, Jin and Zhang, 1992 etc.