本文將經濟投票理論應用至台灣縣市長選舉，以台灣21個縣市在1989年至2001年4屆的縣市長選舉作為研究對象，探討致使地方首長選舉結果出現政黨輪替的可能變數，以彌補現有文獻僅考量政治層面、以及中央層級選舉之不足。經由probit模型估計後發現，地方失業率於選舉年惡化並不會影響縣市長選舉結果；反而是全國失業率對選舉結果有顯著影響。一般而言，總統政黨執政之縣市皆較非總統政黨執政之縣市不易發生政黨輪替，但若全國失業率於選前攀升，則前者所享有的相對優勢會因此而降低，連帶使其被輪替的機率提升。而現任者競選連任則有利於現任執政政黨於選戰中勝出。最後，一黨連任屆數與其發生政黨輪替的機率呈正向關係。 This paper applies the economic voting theory to analyze the county magistrates and city mayors elections in Taiwan and uses a county-and city- level pooling data from 1989 to 2001 to examine the possible factors which cause the party rotation of the county magistrates and city mayors elections. After estimating Probit model, the primary finding is that the local unemployment rates have no impact on election outcomes of the county magistrates and city mayors. Instead, the national unemployment rates have a significant effect on election outcomes. Generally, the probabilities of party rotation of the counties and cities ruled by the president's party are lower than others. However, this advantage will be damaged as the national unemployment rate is higher in the election year than that in the previous year. Additionally, the incumbents are more likely to defeat the challengers and renew their term of office. Finally, the longer the governing party rules the county or city, the higher the probability of party rotation for this county or city.