The catch phrase pattern of “bei + XX ”is a very complex pragmatic phenomenon ，involving a variety of linguis- tic and nonlinguistic factors． Based on the theoretical framework of Adaptation Theory ，this study constructs a model of the dynam- ic process of adaptation to describe ，analyze and explain this linguistic phenomenon ，with the findings that this pattern shows in- tense variability ，negotiability and adaptability ，that its emergence ，development and popularity stem from both the diachronic and synchronic adaptation ，reflecting the communicator ’s dynamic adaptation to the contextual correlates and the structural ob- jects as well as the mutual adaptation between the contextual correlates and the structural objects ，and that the adaptation can a- rouse a relatively high degree of salience on the part of the audience and thus contribute to the maximal realization of the commu- nicative intention．