Since 1950s, Taiwan began to show obvious phenomenon of "polarization" in its regional populationdistribution, which quickly caught the eye of government to notice the equality of regional development. Toencounter this problem, government started to pursue regional plan year by year. Until now, regional planshave been implemented for over twenty years, nevertheless the goal of balance population distribution stilldoubts, and thus the topic deserves deeper discussion. There has been quite a body of research literature on population distribution, most of them adoptedstatistical techniques for analysis, although this kind of methodology can demonstrate some trends of population distribution, it has difficulties in understanding the whole picture of spatial change. Meanwhile, relatedstudies have never focussed on the implementation effects of regional plan, and to analyze the change ofregional population distribution by time and space. Under this circumstance, this study will try to develop a better approach for spatio-temporal analysis, byputting theory of spatial autocorrelation and GIS function together. In this way, the pattern of how populationdistribution varies over time in each county before and after the execution of regional plan will be comparedand analyzed, and the results can be further utilized as a reference for future revision of regional plans.