Despite the recent development of Automated Writing Evaluation (AWE) technology and the growing interest in applying this technology to pedagogy, few studies have dissected the effects of using AWE on facilitating learners in foreign language writing instruction. This study not merely examined AWE’s effects upon English as a Foreign Language (EFL) learners in writing but investigated the detail behind. Participants were 20 juniors from the Department of English Language and Literature at Chinese Culture University in Taipei, Taiwan during the spring semester of 2019. All participants were given a pre-test and a post-test for evaluation. Grammarly, a popular type of AWE, was selected and employed as an assistance tool. The students’ test scores were analyzed by t-test. Findings revealed that there was a significant improvement in applying Grammarly. More implications were further presented.