Abstract: Informatization has become one of the important driving in regional modernization and comprehensive strength. Based on 719 study units in the Yangtze River Economic Belt at county scale, this paper builds an evaluation system with four key elements which contain 9 specific indicators to measure the level of regional informatization, and the four key elements are informatization development environment, the level of informatization infrastructure, informatization innovation capability and the level of networking information consumption. This paper aims to reveal differences in the spatial distribution characteristics of the counties and the factors influencing their development level, by means of using a comprehensive method of mean-variance weighting method, spatial interpolation, exploratory spatial data analysis and kernel density estimation. According to the research, four highlights are unveiled:（1) Overall the informationization level shows the significant regional differences, with the eastern coastal cities higher than those in the western interior at county scale in Yangtze River Economic Belt. Moreover, the high informationization level tends to be distributed in the Yangtze River Delta.（2) From the pattern of spatial auto-correlation, the level of informationization appears significant spatial agglomeration characteristics, that is means the number of the High-High regions（HH regions) and the Low-Low regions（LL regions) occupy most and the spatial agglomeration pattern is obvious. The significant HH areas are mainly distributed in Jinhua, Shaoxing, Wenzhou, Suzhou, Nantong, Changzhou, ect. The significant LL areas have mainly concentrated in Quanjiao, Hexian, Zongyang, ect.（3) From the result of kernel density estimation, the spatial level of informationization in the Yangtze River Delta becomes more obvious in the different search radius. The high density is centrally distributed in the Yangtze River Delta.（4) According to the spatial characteristics of informationization level, the mainly impact factors include geographic conditions, the level of economic development, the strategic policy, the personnel training and the innovation of science and technology.