Based on the past experience of the construction of a well-off society, especially that from developed regions, as well as the analysis of the connotation of modernization, an index system of the preliminary modernization has thus been established on the basis of a “five-in-one” overall layout. The index system includes 38 indicators within 5 aspects, namely, economic modernization, urban modernization，social modernization, political civilization and ecological civilization. A dynamic analysis has been made of the development rate between moderately developed countries and Tianyuan district, with its result suggesting that Tianyuan district will achieve its preliminary modernization in 2022, when its GDP per capita will reach 180 000 yuan. What’s more, it verifies scientifically the feasibility of the goal of GDP per capita currently set in Southern Jiangsu, and a further interpretation and calculation has been made of the index weight setting.