Regional economic disparities have been a hot topic in recent academic world. This paper explores the feasibility of coefficient of variance (CV) and exploratory spatial data analysis (ESDA) in investigating the spatial dynamics of regional disparities at county level in Yangtze River Delta by analyzing per capita GDP data from 1999 to 2008. Empirical results show that the overall spatial disparities of regional economy in Yangtze River Delta have been increasing throughout the study period. The polarization effect is beyond its spread effect, which indicates the spatial heterogeneity of the whole regional economy into two different clubs through the process of cumulative causation.