In squad-level human-machine cooperative combat scenarios, reasonably modeling combat activities poses significant challenges due to the sequence of mission constraints and intricate processes. Traditional modeling approaches struggle to consider both static and dynamic aspects comprehensively while also overlooking the concurrent nature of these combat activities. Grounded on the human-machine mixed-initiative command and control (HMMI) framework, and in conjunction with an actual combat process, we constructed a Petri-net model for main activities and the complete process of a HMMI command and control (HMMI-C2). The rationality and effectiveness of the model were verified by analyzing its boundedness, liveness, reachability, and state space. Furthermore, The HMMI-C2 process Petri-net model was compared with the IDEF0 model and the Behavior Tree model, highlighting its superior capabilities in dynamic simulation, concurrent description, and resource analysis. Experimental results prove that the model holds great promise for organizing and managing squad combat behaviors, promoting combat processes, optimizing system configuration, and ultimately enhancing the capabilities of human-machine collaborative combat.