From a positive psychology perspective, this case study explores learners' academic emotions in giving and receiving peer feedback on second language writing and the possible influences of emotions on learners' uptake of peer feedback. The data were collected from five undergraduates at a Chinese university, including semi-structured interviews, stimulated recalls, peer feedback, students' essays and observation notes. Using content analysis, the study revealed 24 academic emotions, including positive, neutral and negative emotions. Positive emotions were found to improve the number and quality of revisions, whereas negative emotions could not necessarily impede learners' revision operations. The findings suggest the dynamic interplay among learners' positive emotions, positive characteristics and harmonious writing community.