With massive utilization of Automated Writing Evaluation (AWE) tools, it is feasible to detect English as a Foreign Language (EFL) learners' lexical application so as to improve their writing quality. This study aims to explore Chinese EFL learners' lexical application to see if AWE-based writing can bring about positive effects of lexicon on linguistics features, especially in word count, word frequency and word density in their writing texts across a series of tracked revisions in University English classrooms and beyond. The findings from both classroom observations and learners' responses to a post-test questionnaire survey reveal that they showed very positive perceptions of AWE-based writing in which they were greatly encouraged to make modifications in each writing task. It shows from data analysis of the writing texts that learners tended to replace simple lexical terms with more academic and concrete ones in revisions. The results signify implications for EFL learning of lexicon and writing, and also for AWE developers. However, it implies from the analytic features of lexicon that learners' lexical modification was limited. This perhaps suggests for further research on learners' lexical modification in AWE-based writing context to see if there is any difference across genders and different levels of achievers. [For the complete volume of short papers, see ED572005.]