This paper mainly introduces the design principles, construction procedures and potential applications of BETC (Business English Textbook Corpus), a dictionary-oriented corpus. We argue that 1) BETC should be designed based on the principles of assisting dictionary compilation, providing systematic business knowledge and addressing pedagogic needs; 2) in constructing such a corpus, we should consider issues relevant to data collection, data processing, corpus markup and corpus structure in order to ensure its applicability to dictionary-making; 3) BETC proves useful in supporting various aspects of dictionary-making, including lemma selection, label, grammar, semantic division, collocation, exemplification and learning column. This study has implications for the construction of business English corpus and compilation of business English learner dictionary.