Premised on ESP theories and social constructivist learning and assessment models， this study set out to design， implement and evaluate a Business English Communication course for Chinese tertiary students in joint programmes at Shanghai University of Finance and Economics， aiming to promote business communication competencies and higher-order thinking skills． Participants were 361 sophomores from different disciplinary backgrounds and seven college English teachers with varying teaching experiences． The students experienced a designed ESP teaching and learning environment utilizing PBL instructional approach with contextualized writing tasks and multiple assessment strategies． Data collected include pre-and post-tests， selfreported questionnaires， course evaluation， in-depth interviews， and written learning reflections． Questionnaire survey and course evaluation results suggested positive design effect on both communication competencies and higher-order thinking． Qualitative analyses of the interviews and reflections unraveled the important contextual factors that contributed to the student positive changes． This study theorized effective ESP course design principles that will inform pedagogy and teaching practices of ESP and other languages．