Embedded systems are widely used in various devices. PRES+ (Petri net- based Representation for Embedded Systems) has been used to model and analyze embedded systems. However, it cannot characterize the priority of events, and cannot fully express the complex data flow and control flow. To solve this problem, inhibitor arcs are added to PRES+ and PIRES+ (PRES+ with Inhibitor arcs) is obtained. However, PIRES+’s state space explosion problem is a handicap when modeling, verifying, and controlling complex, large embedded systems. To mitigate the state space explosion problem of PIRES+ and analyze complex embedded systems, we propose the place refinement approach and the place set refinement approach for PIRES+. Under specific conditions, several important properties of PIRES+, such as timing, functionality, reachability, liveness, and boundedness, are preserved by using these refinement approaches. In order to illustrate the effectiveness of these refinement methods, as an example, the modeling and analysis of a network communication system is proposed. The refinement methods proposed have certain feasibility and practicability and provide a more practical theoretical basis for the modeling of some embedded systems.