Considering the vital role of college teachers' teaching engagement in guaranteeing the quality of higher education, this study aimed to reveal the behavioral mechanism of Chinese college teachers' teaching engagement through qualitative study based on the grounded theory. It is found that the behavior of Chinese college teachers' teaching engagement is the result of the corresponding intention, which is affected by the three factors of the teaching engagement values, the perceived expectations from the significant others, and the professional knowledge and ability to teach through different ways of interaction. According to the findings, the teaching engagement of college teachers needs to be promoted from three paths: improve teachers' satisfaction of values demands in teaching engagement, reform policy regimes to create a cultural atmosphere that emphasizes teaching engagement, and enhance teachers' professional knowledge and ability of teaching.