It is important to predict the fracture of a joint when designing a composite model. However, when designing a large scale model using finite element analysis, joints can not be considered due to the number of elements and the analysis time. Therefore, in this study, a fracture prediction system for mechanically fastened joints was constructed using a modelica. This system can obtain results in a short time without complicated analysis. To construct this, a response surface (RS) equation is needed. The RS equations of the mechanically fastened joints were taken as the variables of width, tightening force, friction coefficient and hole position. The prediction system consists of a fracture prediction component, a properties component, a modeling component, and a component that displays the results. Using the fracture prediction system of the mechanically fastened composite joint made in this study, it is possible to derive the fracture strength in a short time and it can be used as a component of other system.