Abstract: To study the dynamic changes in urban expansion in Taiyuan，extracting urban built-up areas using
DMSP/OLS( Defence Meteorological Satelite Program/Oprational Linescan System) nighttime lighting data
combined with statistical data method，weighted center of gravity transfer method is proposed to extract the
center of gravity of a city． The main research areas are the spatial and temporal characteristics of land
expansion，the type of urban expansion，and the shift of city center of gravity based on light intensity． The
results show，Taiyuan City's urban built-up area continues to expand and the city's center of gravity is moving
southward． From 1992 to 2012，the main expansion trend of Taiyuan City is westward and southwest and
enhance the dominant expansion type for filling． From 2002 to 2012，the intensity of expansion is especially
obvious，the main expansion trend is south and southeast and is leading type of extension．

Key words: defence meteorological satelite program/oprational linescan system ( DMSP/OLS ), urban expansion, weighted center of gravity transfer method, statistical data method