This project, as part of the Max Planck Society Partner Group "Transmission and Interactions in Chinese Modern Physics," will study the establishment of modern theoretical cosmology in China in the twentieth century, including the field's genesis, the ups and downs of the process, and the Chinese physicists and physics groups that played a significant role. It will focus on two aspects of this long-term development. First, it will examine the transmission of modern theoretical cosmology from Europe and the USA to China, exploring how the transmission of certain cosmological theories, relevant discoveries, and breakthroughs influenced the study of modern theoretical cosmology, as well as the role of the external environment (including cultural, political, and social factors) in transmission. Secondly, it will investigate knowledge production in the field of theoretical cosmology by Chinese physicists and physics groups. To achieve its goal, this project will analyze how cosmological knowledge was produced by the main figures and groups through their research ideas and methods, means of acquiring information, communication with foreign researchers and study groups in other countries, and major contributions to the process. This detailed analysis will be based upon primary documents and second-hand literature.