Peer review is widely used in writing courses for both practical and pedagogical reasons, but little has been published on the characteristics of Chinese EFL learners' review patterns. This study aimed to explore the types of peer comments, their distribution, and related factors in a Chinese context. It collected and analyzed in NVivo and SPSS 829 peer reviews, survey data, and students' writing and reading scores. Results show that more than half of the comments focused on language, one third on social talk, and about ten percent on content and organization. Multiple regression results show that content score, organization score, good attitude, procrastination, and assignment type were related to the distribution and the length of comments, but many other influencing factors are to be revealed in future research.