The development of mechatronic systems can be challenging. The growing complexity and interdisciplinary dependence of systems require close collaboration and uniform system understanding by all the parties involved. The cross-disciplinary system description in the form of a system model can potentially face this challenge. A key aspect is the system structure, which describes the elements and their relationships in the system. The cross-disciplinary way of working requires a comparable, complete and correct description of the system structure, which is expressed by using the word “plausibility”. A framework was developed to model a plausible system structure. The main focus lies on guidelines for the description of the system structure. In addition, the framework consists of a plausibility check, a concept for a software tool and a process model. Thereby the process model describes the cross-disciplinary creation, the formalized computer-based modeling and checking of the system structure. The framework is applied on two products: a pedal-assist and a sorting system. While the pedal-assist system structure is created in the early phase, the sorting system is modeled subsequently.