This paper is based on the test results of two formats of vocabulary tests given to a class of business English students in a business college in Taipei. First, two types of vocabulary tests form the same resource: 1) word to word translation test (word-list test) and, 2) blank-filling test (completion test), are given to the subjects. In order to achieve a better understanding of the effectiveness of the vocabulary test type for L2 learners, the test results are compared. In addition, feedback from test-takers after the two tests are collected to reinforce the accuracy of this project. Second, investigation into what aspects of word knowledge are being tested in the two different vocabulary test types, is also discussed in this paper.