此篇論文旨在探討藉由詞彙判斷作業做為英語為外語者英語書面詞彙能力測量指標的有效性。在此研究中，一方面採取傳統上測量詞彙能力的詞彙翻譯作業，做為詞彙能力測量的指標，另一方面，採用詞彙判斷作業，請受試者勾選所呈現的英文詞是屬於真詞或假詞。研究結果發現，兩種作業成就分別與受試者的各項大型英語測驗成績達到統計顯著相關，顯示這兩種作業都能反應出受試者一般性的英語能力。更重要的，兩種作業間也達顯著相關，顯示紙筆詞彙判斷作業可以視為測量詞彙能力的指標之一。紙筆詞彙判斷作業具有施測時間短，無須人工判斷計分的優點，可以做為網路或電腦施測的英語詞彙能力測量。 The research was conducted to examine whether lexical decision task can be employed to measure the English vocabulary knowledge of EFL (English as Foreign Language) learners. Two tasks were used in the research. One was a traditional vocabulary measurement task， in which subjects were asked to translate the English words into Chinese. The other was an English lexical decision task， in which subjects were asked to distinguish words from pseudowords. The performances in the two tasks were highly correlated， and each one was also correlated with the English scores in the college entrance exams and the scores of an NCU-administered English proficiency test. The results demonstrated that English vocabulary knowledge of an EFL learner can be measured by lexical decision task.