The Geological Society of China was founded one hundred years ago. The pioneers erected the banner of Chinese geological science, which was also the first banner of Chinese science. Since then, the development of geological sciences in China has entered the fast lane. The Yanshan (Yenshan) Movement, the Fusulinida in northern China, the Productus researches and the discovery of the skull of Peking man were the symbols of the rapid entry of Chinese geological science into the international track. According to the evidence and data accumulated in the Western Hills of Beijing, the northern Hebei and western Liaoning regions, the A phase of Yanshan Movement, proposed by Wong (1929), occurred 160±3 Ma ago. In the earlier to Middle- Late Jurassic, the region represented by the Tiaojishan Formation and the Lanqi Formation was characterized by strong volcanic eruption and extensive magmatic intrusion (intermediary phase). Overthrusting structures were developed in the later Late Jurassic. The Yanshanian structures were developed till 135 Ma in earlier Cretaceous, and the unconformity beneath the Zhangjiakou Formation in northern Hebei and the Yixian Formation in western Liaoning Province is representative of the end of B phase of the Yanshan Movement. The Yanshan Movement is a result of the transformation of the East Asian continental tectonic regime from the suturing of Paleo- Tethys and Paleo- Asian oceans to the onset of subduction of the Paleo- Pacific Ocean along the eastern Asian continental in later Jurassic to earlier Cretaceous during ca.160~135 Ma. This is a unique and significant tectonic event in East China and East Asia during the Mesozoic.