The main frame of a jet loom is a very important part supporting the other parts of the operating system, thus, the dynamic characteristics of main frame was investigated in order to analyze the dynamic characteristics of jet looms. In this study, a finite element model of the main frame of a jet loom was developed as a part of an examination of the dynamic characteristics of jet looms. Dynamic analysis of a complex structure system is usually accomplished by analyzing its finite element model. When the total number of degrees of freedom in the model is too large even for modern digital computers to handle economically, recourse is often taken to use the component mode synthesis (CMS) approach. Of the CMS method, the fixed-interface CMS method, which was applied to modeling of main frame, is presented in this paper. In this method, equations of motion were assembled on the truncated normal modes of components, complemented with static modes and developed in a general matrix form for structures with any number of components. Not only does the present method reduce the degree of freedom of the main frame, but its results were in good agreement with results obtained by analyzing the full finite element model.