Li Siguang (1889 ~ 197 1) is a Chinese geologist and the founder of geomechanics. Zhong Yan is from Huanggang, Hubei. Joined the League in his early years and participated in the Revolution of 1911. Geomechanics was founded in the 1920s and made great contributions to geological theory. He studied the phenomena of crustal movement from the viewpoint of mechanics, regarded various structural features as the results of in-situ stress activities, established the basic concept of geomechanics, provided a new method for exploring geological natural phenomena, opened up a new way for studying the laws of crustal movement, and created a new situation in geological science, enjoying a high reputation in the world. His theory has made great contributions to oil exploration in China. For example, he used geomechanics to analyze the geological structural characteristics in eastern China, and thought that the three subsidence zones of the Neocathaysian structural system had broad prospects for oil exploration, which theoretically denied China's theory of poor oil. The successive discoveries of Daqing, Shengli and Dagang oil fields confirmed his scientific foresight. In seismic geological work, he emphasized observing the change of ground stress on the basis of studying geological tectonic activities, which pointed out the direction for realizing earthquake prediction. In addition, as early as the early 1920s, Li Siguang visited the foothills of Taihang Mountain, Datong Basin, Lushan Mountain and Huangshan Mountain in China, and successively discovered the remains of Quaternary glaciers, overturning the erroneous conclusion that many international glaciologists asserted that there were no Quaternary glaciers in China. Li Siguang studied in Japan and Britain, and visited France, Germany and Switzerland. 1949 was a professor in the Department of Geology of Peking University and director of the Institute of Geology of Chinese Academy of Sciences. After 1949, he successively served as vice president of China Academy of Sciences, director of China Institute of Paleontology, member of the Department of Geology of China Academy of Sciences, chairman of China Association for Science and Technology, and minister of Geology, and was elected as deputy to the first, second and third National People's Congress, vice chairman of the second, third and fourth Chinese People's Political Consultative Conference, and member of the ninth Central Committee.