The pedagogical values of corpora for ELT have been widely acknowledged and exploited, but their direct application in classroom teaching has entailed many difficulties. This project aims to investigate the impact of the pedagogical application of corpora on the vocabulary ability of intermediate-level ESL learners in mainland China. This quasi-experimental research study was conducted primarily using pretests and posttests of vocabulary knowledge with one experimental group and one control group of 15 respondents in each group, respectively. Findings indicate that the pedagogical application of a corpus with adequate instruction is more effective and efficient in improving learners' vocabulary. It is hoped that this research can contribute significantly to the education of ESL learners within the Chinese context by promoting more informed, curious, and critical engagement through English lexical learning.