Based on previous researches as well as the characteristics of Business English Major, the authors designed an instrument for assessing college students’ perceptions of business English teachers pedagogical content knowledge. The procedures are as follows:1) Constructing five dimensions of the instrument based on previous researches as well as the characteristics of businessEnglishmajor;2) Compiling 32 descriptive items for all dimensions according to the results of in depth interview with studentsandteachersaswellasconceptmapsfromstudents;3) Revising the content in accordance with suggestions from teacher educationexperts;4) Conducting a pilot study and revising the items accordingly; 5)Conducting the pilot study again. Results of analysisindicatedthatthisinstrumentshowedpromisingvalidityandreliabilityandcouldmeasurethelevelofPCKappropriately. Five dimensions finally constructed in this study were Knowledge of Educational Context and Teaching Objectives, Subject Matter Knowledge, Knowledge of Instructional Strategies and Content Representation, Knowledge of Teachers and Students as well as KnowledgeofCurriculum.ThisstudyenrichestheresearchmethodforthefieldofTeacherKnowledge.