Abstract: To solve the difficult problem that the large-scale composite components, especially the large-scale structure with thin shell, deform easily in the molding, the internal reasons for deformation are analyzed from laminating design, mould material and curing process. It is found that the dimension precision of the large-scale composite structure can be controlled effectively by reasonable laminating design, adopting mould materials with similar liner expansion coefficient and controlling the internal and external temperature environment and molding pressure. These methods are proved effective and feasible by production of the large-scale composite fuselage.