Mobile computing is a new computing technology which is developed after mobile communication and distributed computing technology. The analysis and research on the interaction with mobility can improve the system construction, the business restructuring and the quality management in the complex business process. Firstly, the pi-calculus is proposed as the basic language for the formalizing of mobile communication based on the analysis and redefinition of the interaction with mobility. In the sense of the structural congruence, a formal framework of the interaction with mobility is constructed by defining the general unit and the unit instance based on the mobility of channels in the pi-calculus. At last, the semantic correctness of the formal framework is simulated and derived according to the structured operational semantics of the process algebra.