Teaching efficacy is teachers’ perceived belief and judgement on the locus of control and ability of their teaching. Teachers’ teaching efficacy should be considered carefully because it has a big influence on their teaching effects. In order to diagnose and assess teacher expertise, it is necessary to develop a tool by which the level of a teacher’s teaching efficacy can be judged validly. Based on this necessity, this paper intended to identify elements of teaching efficacy and develop a scale to measure teaching efficacy. To achieve the goal of study, literature reviews on types of teaching strategies, teachers' perception on teaching strategies, and the elements and scale of teacher efficacy were conducted, which led to the tentative elements of teaching efficacy. Through validated validity review and exploratory factor analysis, teaching efficacy scale composed of 5 components and 37 items was identified. Teaching efficacy scale identified in this study is expected to be utilized to diagnose and evaluate teachers' expertise, which can make a contribution to teacher professional development.