This study examined the determinants of party competition in Taiwan. Since Taiwan's socioeconomic development is closely related to the growth of the opposition in the last 20 years, the major hypothesis was that areas with higher levels of development will foster stronger opposition power and eventually more intense political competition. This hypothesis was tested with Taiwan's 1983 and 1986 areal-unit data by controlling for the TCSA (1983) and the DPP (1986) nomination strategy, the local economic conditions (unemployment rate), the age structure (percent of young voters), and the provincial composition (percent of Hakka and Mainder, respectively) in the regression analysis.The results indicate that all factors in the regression model reveal expected results and have statistically significant effects on party competition except for the percent of Hakka variable in the 1986 model. Above all, the socioeconomic development and the party's strategy have the most important influence. Since Taiwan has been facing the transitional stages in economy,society and politics, it's worthy of paying attation to this finding.