English writing, an indispensable skill in English learning, plays an important role in improving learners' language proficiency. With the wide spread and use of wired or wireless internet, EFL students can easily help and be helped with English writing. Therefore, the application of internet-based peer feedback training on writing to foreign or second language teaching and learning has opened up new possibilities for EFL students to improve their writing. Based on the theory of scaffolding and a computer-aided collaborative learning platform, the present study explored the effectiveness of internet-based PFT on 80-sampled Chinese EFL college students' writing error correction and their writing proficiency improvement. The findings of the study showed that 1) the internet-based PFT had positive effects on the improvement of EFL college students' writing, 2) compared with the more-proficient students, the less-proficient students made greater progress in their writing after the internet-based PFT on error correction and they became more capable of correcting both local errors and global errors, thus raising the quality of their writing error correction, 3) the more-proficient group showed no trust on the received peers' feedback because of the entrenched prejudice that their peers were incompetent for revising English writing.