Recent scholarship has called for deeper communications and collaborations between writing studies and language studies because such interdisciplinary connections can facilitate the growth of both fields. While research has explored the potential exchanges between writing studies and language-related fields (such as applied linguistics, second language writing, and sociolinguistics), few studies have focused on the intersections between English historical linguistics and writing studies. This article partially fills the gap by demonstrating how a diachronic corpus-based approach from history of the English language research can be an effective methodological tool for historical research in writing studies, which has been of great interest to writing studies scholars. This article first offers three reasons why a diachronic corpus-based approach can methodologically contribute to historical research in writing studies, and then it illustrates the practice of such an approach by studying the changing disciplinary trends in writing studies from 1997 to 2022 in a self-built, diachronic corpus. To identify the disciplinary trends, word frequency lists and keyness analysis (TF-IDF as procedure) were used. The results indicate both perennial interests and five-year, periodical activities in writing studies over the past 26 years.