Abstract: The study aims to explore the effects of peer feedback on 152 non-English freshmen's English writing anxiety and their writing ability, through the comparative study between the experimental group and the control group before and after the peer feedback experiment. The experimental group adopts the mode of peer feedback + teacher feedback and the control group completely relies on teacher feedback. The results report firstly a significant reduction in the experimental group's English writing anxiety, especially in the factors of classroom teaching anxiety and lack of confidence; whereas the other two factors of conceiving anxiety and avoidance behavior show no significant difference. Then peer feedback substantially helps to improve students' writing ability. The findings indicate that in teaching writing, peer feedback and teacher feedback should be combined to reduce students' English writing anxiety, to improve their writing autonomy and writing ability.