Engineering education accreditation is considered fundamental reforming orientation to the institutional constructions of talent cultivation for engineering majors, while technology competitions for college students are also considered important approaches to achieve the educational objectives and graduation demands under engineering education accreditation. On the understanding that guidance to technology competitions is dealt with in light of the 3 core ideas of engineering education accreditation, including student-centered, comprehensive ability outcome-based and continuous quality improvement, the structural equation model (SEM) of the competency of guiding teachers is established with competency concepts and principles. Moreover, assumptions of SEM model are proved and formation mechanisms of the competency of guiding teachers are analyzed through a case study of NACtranS. It is suggested that the competency of guiding teachers is consisted of 3 dimensions, including topic selecting, works producing and team managing. While there are 10 characteristic vectors related to the 3 dimensions and 5 of them have more obvious direct influence on these dimensions. The hierarchical differentiation and regional differentiation of colleges are the main reasons for topic selecting performances and works producing performances of guiding teachers through indirect interference of intermediate variable. Countermeasures to improve the competency continuously can be raised by both effects achieving in the short time and connotation constructing in the long run.