This paper examines the spatial polarization of regional economy in the three provinces of Northeast China. Municipal jurisdiction, city proper and county were respectively used as the basic units of analysis, for each of which the GDP and per capita GDP as collected or calculated. The degrees of inequality and polarization of regional economy for the years of 1990, 1995, 2000 and 2005 were evaluated with Gini Coefficient, Wolfson Index, and TW Index. Spatial autocorrelation analyses were employed to identify the "hot places" of economic development, and explore the patterns of polarization of regional economy, of which city proper and county were basic units.The research reveals that the polarization of regional economy progresses in each of the three units mentioned above in Northeast China since 1990, and the city district economy is the most polarized among them. A spatial trend has been exhibited for economic center of gravity to move southward. The areas with high value in spatial autocorrelation analysis have been turning from scatters to axial and planar distributions. Dalian, Shenyang, Changchun and Harbin, are high "polarizing points", and discontinuous "polarizing axes" are along Harbin-Dalian and Manzhouli-Harbin-Suifenhe railroad. The area with High value covers all the Middle-and-South Liaoning, meanwhile, low value areas extend in North Heilongjiang, East and West Jilin, and West Liaoning, and become more continuous.The polarization results in that in Northeast China, regional economic system tends to become less hierarchical, and the economic growth among prefectural cities, with the Four Cities excluded, tends to become equality. The polarization also brings varying degrees of developments to Middle-and-South Liaoning Economic Region, Harbin-Changchun Region (Harbin, Daqing, Qiqihar, Songyuan, Changchun, and Jilin City), Manzhouli-Harbin- Suifenhe Economic Axial Belt, the major structures of regional economy in Northeast China.