Our recent structural survey of the Niuyingzi region, western Liaoning shows that there exist a thrust of the latest Triassic age, which is covered by the Middle Jurassic Guojiadian formation in the eastern Niuyingzi region. The directions of thrusting are toward the east for the principal imbricated sheets just west of Huangtupo and toward the south for the local arcuate thrust just north of Huangtupo. There occur synthrusting sediments, the Dengzhangzi formation along a trough-like basin, which was controlled by the thrust fault zone. The Dengzhangzi formation is composed of brecciated lime-dolomitic conglomerate. The stratigraphic sequence and structure of the strata confirm that the age of the Dengzhangzi formation is of latest Triassic. It can be observed that the Late Triassic Laohugou formation is transitional to the Dengzhangzi formation successively. Therefore the Late Triassic to Middle Jurassic stratigraphic sequence in the ascending order is the Laohugou formation, Dengzhangzi formation, Shuiquangou formation and Guojiadian formation in this region, instead of the previous reversed order. The confirmation of the thrust system developed in the Late Triassic in this region provides the key evidence to understanding the early stage of the deformational history of the Yanshan intracontinental oro-genic belt.