As a practical model of interdisciplinary construction, the Business English major is evolving in its goals from the traditional “language + business” model to the three-dimensional collaborative paradigm of “language-business-literacy”, which poses new challenges to the interdisciplinary knowledge integration ability of the teaching staff. At present, the Business English teaching staff faces contradictions: full-time teachers have a single disciplinary background in linguistics, are expert at language skill training, but lack sufficient business knowledge and practical experience. This study combines domestic and foreign research models of competency to systematically deconstruct the elements of Business English teachers’ interdisciplinary knowledge integration competency. By analyzing the integration characteristics of Business English with business disciplines, this paper explores its specific manifestations in teaching practice and constructs a three-dimensional competency model that includes language ability dimensions, core competency elements, and connotative expansion capabilities.