Peer Response is an approach to help each other in revision. However, such a collaboration approach usually has to face a challenge of higher time cost for information sharing, in particular, in a paper-and-pencil based environment. Therefore, the aim of this study is to investigate how to implement a computer supported peer response approach at elementary writing classes and evaluate the effects of this approach on writing improvement. Latent semantic analysis was used to analyze the richness of vocabulary in writing and a questionnaire was used to investigate pupil's perception towards such a peer response approach. We found that this approach not only enhances the communication between student readers and writers, but also expands their length of writing and improves the richness of vocabulary in revision. Meanwhile, it is found that both peer writers and peer readers can benefit from this computer supported approach, such as promoting self-reflection or increasing motivation for revision. To the end, all elementary participants showed a stronger agreement on the perception of peer response on writing.