This article reports an investigative study on the target language use in and outside business English classrooms for non-English major undergraduates in a Chinese university context. The aims of the study are to identify the actual situation of target language use in business English teaching and to suggest ways for improvements. The study uses the research instruments of questionnaires containing rating and open-ended questions, and participant observation of 128 participants from different academic disciplines enrolled in business English courses. The results show that although the teacher talk ratio of target language and first language (L1) use is 90:10, the participants' target language use in various communicative contexts in and outside the classroom is inadequate. The constraint factors include study environment, L1 and other languages, low English proficiency, personality and limited resources. Pathways to improve the English language learning environment are thus suggested. This study informs business English teaching practices, curriculum implementation, and language policy development under the background of new College English Teaching reform in China within the international context.