The development of corpus linguistics has laid theoretical foundation and provided technical support for breaking the bottleneck in traditional vocabulary instruction in China. Corpora allow access to authentic data and show frequency patterns of words and grammar construction. Such patterns can be used to improve language materials or to directly teach students. Therefore, this paper discusses how the Corpus of Contemporary American English (COCA) can be applied in vocabulary instruction in the following four different aspects: part of speech, collocation, morphology and word comparison. The above four aspects of application of COCA in vocabulary instruction and their examples have proved that corpora are robust in teaching.