胡焕庸线的学术思想源流与地理分界意义

In the early 20th century, China was faced with domestic crisis and foreign invasion, and the man-land contradictions were unprecedented fierce. Geographers pondered and explored the issues of national fortune such as China's population status, northwest exploitation and internal migration, thus China's population geography emerged as the times required. "The distribution of population in China" published by Hu Huanyong in 1935 is a symbol of maturity of China's population geography. The Hu Huanyong Line (also known as Hu Line) proposed in this paper, which he originally called the Aihui-Tengchong Line, is a significant geographical demarcation of China's population. The existence and stability of the Hu Line have been repeatedly verified by census data, and its scientific principles have also been revealed and explained by the academic circles from aspects of nature, economy, social culture, etc. This paper points out that grain and employment are the two hidden logics behind the Hu Line. The Hu Line is becoming a crucial national geographic demarcation, which has an increasingly essential impact on the cognition and analysis of China's national conditions. Recent research on the Hu Line has been widely extended in various fields and meanings, and there arose some amendments and adaptations of the line in practice. Under the influence of "Premier Li Keqiang's three questions", whether the Hu Line can be broken through has become an academic hot spot. This paper holds that it is more important to create more opportunities of the northwest region than to increase the share of population so as to balance regional development.