Based on the concept of spatial polarization, this paper built up a regional development index from the perspective of element flows, which is called urban agglomeration ability, and analyzed the regional development evolution in the three provinces of Northeast China from 1995 to 2008 on the whole. Secondly, the paper used the difference indexes and polarization indexes to measure the degrees of inequality and polarization of the regional development in Northeast China for different concentration levels. The results show that: (1) from the viewpoint of the dynamic evolution of the patterns of regional development, from 1995 to 2008, the regional development of Northeast China had an undulating course, and the overall level was slightly decreased. The agglomeration ability and its evolution trend showed that the center cities, the traffic hub cities and the resource cities played an important role in the regional development pattern evolution. It was showed that the four cities showed that the development trend was increased from north to south. The formed city economic zones began to present their functions, and the Harbin-Dalian Railway became a discrete"polarization axis". The regional development center was gradually moved to the south with the differences of the regional development. (2) The whole region showed a growing trend, in which the municipal administrative areas had a higher degree of polarization than the county level subdivisions, with different directions of evolution. The spatial distribution of inequality index had a sequence of Liaoning Province > Heilongjiang Province > Jilin Province, and the TW index showed a sequence of Heilongjiang > Liaoning > Jilin. The resources cities had an absolute decline, and had a lower polarization degree than the non-resources cities.