A certain type of equipment-loaded vehicle system is a special vehicle designed according to the operating requirements of motor vehicles. The work aims to meet the demand of missions and tasks, improve its availability to a certain extent, and analyze its maintainability requirements. An ergonomic design parameter system focusing on the core evaluation index of maintainability was established. Ergonomic design principles such as "simplified and modular design, good testability and accessibility, perfect error prevention and identification mark design, and ensuring the safety of maintenance" were determined. Common system modeling methods, such as Petri net, IDEF, UML and eEPC were compared. The event driven process chain (eEPC) method was selected for modeling. Collecting and counting the maintainability related data in the test and trial stage of this equipment-loaded vehicle system, deploying targeted analysis and discussion through the eEPC process model, and giving measures and suggestions for the improvement of its maintainability ergonomic design can shorten the preventive maintenance time and repair maintenance time, and speed up emergency response and improve mission reliability.