The flipped classroom has been achieving a great success in teaching innovation. This study, aiming to determine the effectiveness of the flipped model in business English writing course, combined the quantitative with the qualitative research methods. Participants were randomly selected from undergraduate students majoring in business English. The research instruments in this study included a satisfaction scale, a Business English Writing Test, and a semi-structured interview. The research procedure was made up of a pretest— treatment—posttest design. Both hypotheses were accepted and it was concluded that (1) the flipped business English writing classroom brought about better academic achievements than the traditional one, and (2) the flipped business English writing classroom was more satisfactory than the traditional one. Future studies could pivot on different courses and expand the research scopes to examine the effectiveness of the flipped classroom.