In the Late Jurassic a narrow EW subsidence belt over 1200 km long developed in the Yan-shan-Yinshan area,in which were mainly accumulated thick coarse-grained elastics with the nature of red beds. Its formation reflected that an intense thrusting-uplifting event occurred in this area at that time. The event, which occurred in the tectonic setting of compression from north to south, was closely related to the closure of the Mongolia-Okhotsk sea basin and collision orogeny of the Mongolia-Okhotsk belt to the north of this area. The existence of the Yan-shan-Yinshan huge EW nappe structures reveals that the influence of the Tethys or Paleo-Pacif-ic ocean dynamic regime continued to the Late Jurassic, and afterwards the evolution of the dynamic regime of the area entered a new stage.