On this day, 130 years ago, January 22, 1895 (December 27, 1894 in the lunar calendar), China sociologist and social researcher Li Jinghan was born. Li Jinghan (1895.1.12-1986.9.28) is a famous sociologist and social survey expert in China. Born in Tongzhou, Beijing. In 1917, he went to the United States to study, majoring in sociology and social survey research methods. He studied at the University of Colombia and the University of California, and obtained a master's degree from the University of California. He returned to China in 1924 and served as an officer of the Peiping Institute of Social Investigation. In 1926, he served as director of the Social Investigation Department of the China Education and Culture Foundation and lecturer in the Department of Sociology at Yanjing University. In 1928, he served as director of the Investigation Department of the Dingxian Experimental Zone of the China Association for the Promotion of Civilian Education. 1935-1944 In 1999, he served successively as a professor of the Department of Sociology at Tsinghua University, director of the Investigation Team of the National Survey Institute of Tsinghua University, and professor of the Department of Sociology at Southwest Union University. 1944-1947 In 1947, he was sent to the U.S. Census Bureau for inspection and participated in population research activities. From 1947 to 1949, he worked in the Statistical Expert Office of the Food and Agriculture Organization of the United Nations and served as an agricultural census consultant for several Southeast Asian countries. 1949-1952 In 1999, he served as the chairman of the Department of Sociology at Fu Jen Catholic University and took part-time courses at Peking University. In 1953, he served as a professor at the Central School of Finance and Economics, Renmin University of China and Beijing School of Economics. In 1956, he served as director of the Research and Research Office of Renmin University of China. In 1979, he was hired as a consultant of China Sociological Research Society; In 1984, he was hired as a consultant at the Institute of Sociology at Renmin University of China. Li Jinghan has made contributions to social survey research and sociology teaching in China. He conducted a large number of social surveys, of which the survey conducted in Dingxian County is one of the models for China intellectuals to use Western sociological methods to conduct field surveys. It is the first systematic field survey in China based on counties. The book "Social Survey of Dingxian County" provides detailed information for the study of rural communities in northern China in the 1930s and has had a profound impact at home and abroad. His main works include "Survey of the Current Situation of Rickshaw Drivers in Beijing"(1925),"Survey of the Proletarians in Beijing"(1926),"Rural Families in the Outskirts of Peiping"(1929),"Field Survey Methods"(1933),"Survey of Social Survey in Dingxian County"(1933),"Notes on Survey of Rural Family Life in Beijing's Suburbs"(1981), etc.