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 by engineering education accreditation. On the understanding that guidance to technology competitions is dealt with in the light of 3 core ideas of engineering education accreditation, including student-centered, comprehensive ability outcome-based and continuous 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 according to SEM of NACtrans case. The hierarchical differentiation of colleges is the main reason for topic selecting performances of their guiding?teachers through indirect interference of intermediate variable in SEM of NACtrans case, as well as regional differentiation of colleges for works producing performances. Countermeasures to improve the competency continuously can be raised by both effects achieving in the short time and connotation constructing in the long run discussed above.