The modeling and simulation of large-scale Device Collaboration systems is an important issue for seamless integration and collaboration of distributed device integration. Based on the advantage of PI-Calculus in modeling concurrent and dynamic systems, a method concentrating on the modeling of large-scale Device Collaboration system is presented. Firstly, it transforms device behaviors and interactions into PI-Calculus processes. Secondly, weak dissimulation of multiple internal control flows is defined through the application of behavior equivalent theory of PI-Calculus. Following that, external behavior equivalence of system dynamic ontology is discussed. With the help of operational and transitional semantics and a formal deduction, our method can discover system problems in design stage, thus improving architecture correctness and execution stability of Device Collaboration systems.