The political context to which the electorate is exposed is filled with a variety of political information and becomes more and more competitive during political campaigns. This seems to mean that a given campaign facilitates the electorate to create for itself clearer and more drastic political preference based on party identification up to voting day. The author utilizes the pre-election survey data from rolling cross-sectional telephone interviews during the 2012 Taiwan’s presidential election to detect the influence of party identification on candidate evaluation during the political campaign. It was found that the electorate had a significantly clear preference between the main candidates up to voting day, especially for the more involved voters. Furthermore, the correlations between voters’ party identification and its political attitudes including candidate evaluation and government performance become increasingly tighter as voting day approaches. In conclusion, this study proves the reinforcement of the party identification effect during political campaigns and suggests that it would be worthy to investigate it in a different political context in the future.