This study was inspired by Qian (1999) and Staehr (2009) and researched 88 Chinese learners who had already passed the College English Test 4 (CET). These learners volunteered to participate in the study regarding the depth and breadth of vocabulary knowledge and its relationship with listening comprehension, which was assessed by analyzing the results of a series of comprehensive tests including the vocabulary size test (VST), depth of vocabulary knowledge (DVK), and listening comprehension test (LCT). The findings suggested that a vocabulary level of 5,000 word families had a higher correlation with academic listening comprehension (r = 0.86), while a vocabulary level of 3,000 word families had a lower correlation with a lower listening comprehension (r = 0.41). This is evidence that outstanding listening scores require a larger vocabulary size than does reading. This study also showed that the depth of vocabulary knowledge provided a higher correlation (r = 0.91) with listening comprehension and a higher predictive power in listening comprehension than the breadth of vocabulary knowledge. A multiple regression analysis was used, and the R[superscript 2] change was 2.6% when adding DVK to VST, which demonstrated that the depth of vocabulary knowledge had a significant predictive power on the scores of listening comprehension. This showed that attention should be paid to this area, with teachers as well as learners, in China as well as in other EFL contexts in future teaching and learning of listening comprehension.