Existing legislative theories, which are developed to explain legislative dynamics in the U.S. Congress, presumes the existence of a majority party in a legislature and fails to provide predictions about positive agenda power of a majority under various degree of intra-party homogeneity and inter-party heterogeneity. Offering a theory of legislative majority coalition to explain its positive agenda power and proposal passage in the Taiwanese legislature, where only a single pivot exists, this paper hypothesizes that a majority coalition’s ability to exert its positive agenda power depends on passage costs (e.g., a majority coalition formed by a single party or multiple parties and the size of a majority coalition) and priority of its proposals. We collect all the legislative proposals raised from the second through the sixth term (i.e., 1993-2007) to obtain more robust empirical results and examine the hypotheses derived from our model. Our empirical and qualitative analyses render strong support for all of our hypotheses. Moreover, in contrast to previous empirical findings, we find that divided government does not have any significant impact on government proposals. This finding has profound implications for our understanding of legislative gridlock and the legislative-executive relationship in Taiwan.