In most survey research, it is difficult to evaluate the survey accuracy. The pre-election poll (survey) is unique, since the election result can be used as its target and counting its performance. Indeed, there are hundreds of research improve the survey methodologies through the experimental study from election polls. This study will conduct a panel pre-election poll and post-election poll for Governor of Taipei County 2005. Through comparison of the differences among pie-election poll, election result, and post-election in the designed panel study, three special categories of respondents: undecided, hard-to reach, and refusals and their corresponding election behaviors are investigated. Besides, this paper is focused on the following two issues: boa non-sampling errors might affect the poll accuracy, and how the use of weighting variables might affect the poll results.