Most social and economic activities cluster within the urban areas. Cities play a significant role in the sustainable development of the region due to their own high productivity and spatial radiation. Therefore, the overall buildup of regional sustainable development should begin with the buildup of urban sustainable development, and the nucleated cities in particular have a crucial play in this process. This paper aims at a further understanding of the regional sustainable development through the quantitative assessment of the nucleated cities, the 9 of which cited in the article are all cities of administration centers in Jilin province, namely, Changchun City, Jilin City, Siping City, Liaoyuan City, Tonghua City, Baishan City, Songyuan City, Baicheng City and Yanji City. In terms of population, these cities can be classified into such three types as metropolises, large cities and medium-sized cities. And in terms of administrative level, they fall into one provincial capital city, cities at the prefectural level and at the county level. The article sets forth an indicator assessment system designed to evaluate the sustainable development of Jilin province. The indicators, which can be subdivided into 49 factors, include, 1) Ecological Space & Environmental Quality, 2) Infrastructure & Labor Force, 3) Overall Economic Strength & the Efficiency of Enterprises, 4) Regional Financial Capabilities, 5) Life Quality & Social Security system. All the indicators are determined on the following principles, feasibility, full coverage, per capita factors and cross section data. The author adopts alternatively the Index Method and Factor Analysis Method to assess the sustainable development of Jilin Province, and identifies the Index Method is better fit for the case of Jilin province. The result of the assessment is that Yanji City, Changchun City and Jilin City rank the first three places with their strong regional economic strength. And the last three cities are Liaoyuan City, Baicheng City and Siping City due to their relatively weak economic strength.