This study examined the impact of an artificial intelligence (AI)-supported approach to peer feedback provision on the feedback quality and writing ability of English as a foreign language (EFL) student reviewers. The researchers integrated an AI chatbot named Eva into an online peer review system to assist students in generating feedback. A total of 124 Chinese undergraduate students participated in nine peer review tasks over three weeks, with 64 students in the experimental group (using Eva) and 60 students in the control group (without AI support). Pre- and post-tests were conducted to assess the quality of student reviewers' peer feedback and these feedback providers' subsequent writing performance before and after the intervention. The findings revealed that the intervention significantly enhanced students' feedback quality. Additionally, the study showed that the proposed approach improved feedback providers' writing ability. This research underscores the potential of AI technology in enhancing EFL writing instruction.