Taiwan remained in a relatively closed population environment after the WW Ⅱ, and the changes in population mostly came from the growth of the existing population, instead of migration from outside. To villages and township in counties of Taiwan, the main factor affecting the population distribution and level of urbanization is regional population movement. With research scope on villages and township in Taichung County, this paper discusses the natural population growth and the effect of population change on the total population after war, and explains the basic model of village and township population growth. Lastly, this paper compares the existing division of administrative zones based on the population growth model, and analyzes the most suitable division of administrative zones for the existing population growth. The results showed that the main factor affection the population scale in villages and township in Taichung County before 1975 was natural population growth and that after 1975 was population movement. Concerning the population growth model, the types of population movement in 21 villages and township in Taichung County are "exceeding the expectation" and "not exceeding the expectation". The "exceeding the expectation" type includes "significant population movement type" and "slow population movement type". The "not exceeding the expectation" type, if maintaining the same trend, will become "saturated growth type" and "stagnant growth type". Lastly, the results of classification of different population movement types for the villages and township in periods showed that "industrial development zone division" for five zones is more suitable than "existing zone division" for three zones, except for Houli Township.