A spacecraft liquid propulsion system, which is the primary actuator for guidance, navigation, and control, is critical to mission success and safety. However, this system has potential of several undesirable phenomena and component faults that lead to compromised performance or even failure. This study focused on using analytical and physical models to assess and treat risk in the system. To clarify our model-based approach, this paper proposes a framework that covers the modeling strategy and methodology based on the objective and scope of each risk management process. The framework also updates and integrates the model step by step manner through the life cycle of the system. This feature emphasizes the advantages of the model-based approach, such as inheritance and reusability, comparing conventional approaches that use different models for each domain and phase.