The teaching of L2 writing has always been an emotionally demanding profession, which involves tremendous emotional labor on the part of L2 writing teachers. This study explores Chinese EFL teachers’ feeling rules, emotional labor and regulation strategies in their teaching of L2 writing. Using teacher interviews and classroom observation as primary data sources, the study shows that three feeling rules govern teachers’ expression of emotions in teaching L2 writing: a) take care of student motivation and commitment to L2 writing; b) instead of dismissing student difficulties in writing, seek pedagogical solutions; and c) exercise professional expertise in teaching L2 writing by instrumentalizing emotions. This study also reveals three primary sources of L2 writing teachers’ emotion labor: the conflicts between a) teachers’ expectations and practical difficulties in L2 writing, b) the mandate and uncertainty about how to conduct writing assessment, and c) the willingness and difficulty in conducting dialogues with individual students in L2 writing. In response to the emotional conflicts, L2 writing teachers regulate their emotions by disguising, restraining, releasing, and compromising. The findings provide insights into the emotional dimension of feedback on academic writing and offer implications for both the L2 writing teachers and teacher educators concerning how to alleviate the negative emotions and enhance positive emotions by updating their mindset and pedagogical skills in teaching L2 writing.