本研究應用「沉默螺旋理論」探討2001年台北縣縣長選舉期間，影響選民公開表達意見的因素，並瞭解政治上泛藍與泛綠陣營兩股勢力的選民意見分佈情形。另外，本研究嘗試分析「參考團體」與「第三人效果感知」兩個自變項對「表達意願程度」 依變項的影響力。研究結果發現此次選舉選民的民意形成過程符合「沉默螺旋理論」的假設，亦即，當個人意見與預估未來意見一致時，其表達意願會比個人意見與預估未來意見不一致時來的高。在選民認為他人比自己更容易受媒體影響，而且所支持的候選人與心中認定會當選的候選人是同一人時的前提下，該選民公開表達己見的意願會較高。當參考團體所支持的候選人與選民個人支持對象一致時，其在公開場合表達意見的意願也會較高；不過，在控制個人意見與預估未來意見的一致程度下，個人意見與親友意見是否相同並不影響表達意願。由此觀之，此次選舉的選民並非透過參考團體來觀察大環境的意見氣圍，而是藉由大眾媒介來察知大環境的意見氣候。 This study applied “Spiral of Silence Theory” to testing voters’ willingness to express opinions publicly during the Taipei County Magistrate’ s Election in 2001. The findings supported the hypothesis of “Spiral of Silence Theory”. Voters were more willing to express opinions publicly when their perceptions of the distribution of public opinion were the same as their own. Taking “third-person effect” as the mediating factor, one who believed others would be more influenced by mass media than him/herself was more likely to express his/her own opinion given that the candidate he/ she supported was the same as considered to be elected in the election. Regarding the impact of reference groups on voters’ willingness to express their opinions, only when voters and their relatives (or friends) supported the same candidate, did the former tend to openly express opinions. However, the effect of reference groups was cancelled out when voters’ opinion was identical with their perceptions of the distribution of public opinion. In this election, voters perceived the public opinion climate through the mass media instead of through reference groups.