Take Jilin province central urban agglomeration as the research object, from the point of view about the effect of city location on regional balanced development, and by constructing the measure index of the city location and regional balance index, the paper analysis the time and spatial evolution about ten years central urban agglomeration's county level city location and development between counties, trying to explore the internal influence mechanism. The result shows that: ① In recent years, the regional economic center, population center are all gradually near to Changchun; the city location deviation overall decreased and goes well. ② The urban agglomeration is still in single center polarization phase, the phenomenon of regional economic element agglomeration is obvious; but regional population tends to disperse, especially after 2005, the population gap between counties, between urban and rural areas all decreases. ③ The internal impact on city location and balance of regional development is the shift change of the city level. <<