Joseph Rock (1884-1962), botanist, anthropologist, explorer, linguist, immigrated to the United States from Vienna, Austria in 1905. After having taught botany at the College of Hawaii and published five books and numerous monographs, he was, from 1920 to 1949, dispatched by various United States institutions and agencies (the National Geographic Society, U. S. Department of Agriculture, the Arnold Arboretum of Harvard University and the Harvard-Yenching Institute) to conduct field research and explore in west China. In 1924, Charles Sargent (1841-1927), the first director of the Arnold Arboretum of Harvard University, initiated Rock’s expedition to northwestern China and northeastern Tibet. Rock was assigned to collect plants and to photograph specimens along the Yellow River and in the mountain ranges Amne Machin and the Qilian mountains. Rock also explored along the Yangtze River, the Gansu-Sichuan border, in the Tebbu region and around the Kokonor Lake. One of the most valuable achievements of Rock’s 1924-1927 expeditions, in our view, lies in, along with a large number of maps and photographs that he produced in the field, his field studies of the cultures and languages as well as inter-ethnic relations in this region. Here, we selected one of the many correspondences that Rock wrote to Prof. Sargent dated May 10th, 1925 and translated it from English into Chinese with annotations. We intend to use this letter as an example to show his experience in Gansu in 1925 and reveal his acute observation of ethnic conflicts and political chaos in west China in the 1920s. Aside from his world-renowned personality and unusual view of modern western civilization and industrialization, there are many aspects to Rock’s talents and skills, including the identification and collection of plants, the decipherment of the Naxi pictographic language and competence in about ten languages including Chinese, Tibetan, Arabic and Latin, and the compilation of maps. Although scholarly use of Rock’s contributions to the field is far from enough, increasing attention to and interest in this talented and legendary ethnographer and his adventurers grow among scholarly community. With Rock’s archives at Harvard University (19 boxes of dairy, correspondences, maps as well photographs) put online as original sources, this research is just a starting point of a large project on Rock and his ethnographic endeavors in west China from 1924 to 1927. Joseph Rock (1884-1962), botanist, anthropologist, explorer, linguist, immigrated to the United States from Vienna, Austria in 1905. After having taught botany at the College of Hawaii and published five books and numerous monographs, he was, from 1920 to 1949, dispatched by various United States institutions and agencies (the National Geographic Society, US Department of Agriculture, the Arnold Arboretum of Harvard University and the Harvard-Yenching Institute) conduct conduct field research and explore in west China. In 1924, Charles Sargent (1841-1927), the first director of the Arnold Arboretum of Harvard University, initiated Rock’s expedition to northwestern China and northeastern Tibet. Rock was assigned to collect plants and to photograph specimens along the Yellow River and in the mountain ranges Amne Machin and the Qilian mountains. Rock also explored along the Yangtze River, the Gansu-Sichuan border, in the Tebbu region and around the Kokonor Lake. One of the most valuabl e achievements of Rock’s 1924-1927 expeditions, in our view, lies in, along with a large number of maps and photographs that he produced in the field, his field studies of the cultures and languages ​​as well inter-ethnic relations in this region Here, we selected one of the many correspondences that Rock wrote to Prof. Sargent dated May 10th, 1925 and translated it from English into Chinese with annotations. We intend to use this letter as an example to show his experience in Gansu in 1925 and reveal his acute observation of ethnic conflicts and political chaos in west China in the 1920s. Aside from his world-renowned personality and unusual view of modern western civilization and industrialization, there are many aspects to Rock’s talents and skills, including the identification and collection of plants, the decipherment of the Naxi pictographic language and competence in about ten languages ​​including Chinese, Tibetan, Arabic and Latin, and the compilation of maps.cholarly use of Rock’s contributions to the field is far from enough, increasing attention to and interest in this talented and legendary ethnographer and his adventurers grow among scholarly communities. With Rock’s archives at Harvard University (19 boxes of dairy, correspondences, maps as well photographs ) put online as original sources, this research is just a starting point of a large project on Rock and his ethnographic endeavors in west China from 1924 to 1927.