Abstract: Aiming to investigate the crucial reason of urban sprawl disorder and slow economic development in Northeast China thoroughly， as well as quantitatively reveal the path of spatial-temporal expansion and the driving factors of urban agglomeration， such model indexes as urban expansion hotspots and driving forces with 172 districts and counties in the city cluster of Harbin， Changchun and central-southern Liaoning Province were constructed based on DMSP， VIIRS night images， and urban statistics data. The results indicated that the expansion of urban agglomeration reaches its peak during 2005—2009 and continues to decline after the peak， and the resources of central cities are concentrated while the development of sub-central cities is weak. Centripetal agglomeration centering around Harbin， Changchun， and the economic belt of central-southern Liaoning Province reflects the overall performance of urban agglomeration， with the western and southern areas expanding faster than the eastern and northern areas. The primary/secondary industries， population， and GDP are the main driving factors of urban agglomeration. From the perspective of spatial-temporal trend， industrial structure adjustment， population loss and weakening growth are the main influencing factors of the changes on urban agglomeration. The results of this research can provide reference for the future development planning of the city cluster of Harbin， Changchun and central-southern Liaoning Province.

Key words: night lights; urban land expansion; driving factors; regional coordinated development; Harbin-Changchun and central-southern Liaoning urban agglomeration