The article is an analysis about the evolution of public health in modern Chongqing through thorough search of historical information and reference, and the purpose of the article is to find out the characteristics of the development of public health in modern Chongqing and show their historical and realistically profound instruction for improvement of healthy service today. The results were as follows:  The evolution of public health in Chongqing fell into three successive phases. In the first phase, from the end of 19th century (in this time Chongqing became to a commercial port) to 1926, the mission came to Chongqing and established some missionary hospitals. They made a positive influence on the formation and development of the western medicine in modern Chongqing. In the second period, the Chongqing government commenced to pursue a political goal: urban modernity. As an ideal of urban modernity, the authorities pay a lot of attention to public health which refers to both the appearance of physical environment and the behavior of individuals with that environment. In 1937, the war against