Based on analysis with ESDA-GIS framework, by using statistical data of 1346 small cities and towns in Jiangsu province in 2002, their spatial structure was studied. We, at first, finished summary factor analysis from database, and drew the two principal components: economic factor and scale factor. By comparison, we found that the frequency distribution of the two factors was skewed and the skewed degree of scale factor was higher than that of economic factor. But there is no positive correlation as scale-benefit between the two factors. In this paper, exploratory spatial structure of the small cities and towns was analyzed. With the density map, we found their spatial distribution is imbalanced, whose density would descend gradually from Yangtze River zone and Taihu Lake area in the southeast to the west and the north, which showed a belt and circle structure. Based on the analysis with global SAMs and local SAMs, we came to some conclusions. The spatial distribution of economic factor of the small cities and towns showed positive autocorrelation and spatial cluster, but the autocorrelation of scale factor is very weak. Finally, after classifying the local SAMs coefficients of small cities and towns according to administrative units of country, we analyzed economic significance with anisotroptric variogram and improved the classified result. We found the spatial cluster of the economic development of the small cities and towns in Jiangsu province: three districts, one belt, and one part, i.e., the middle part of the northern Jiangsu area, the middle part of Jiangsu province and Nanjing-Zhenjiang area, Suzhou-Wuxi-Changzhou area, and the northern part of Jiangsu border belt, and district around Suining. The corresponding economic development types are diffusing development type, polarizing development type, clustering development type, transitional development type, and continual impoverished type.