Abstract: For the VARI process molding simulation of big size sandwich structure composites or sandwich composites of complex shapes, traditional modeling method is inefficient as the modeling is difficult and the simulation calculation is large. In this paper, a simple and convenient equivalent modeling method is proposed. in which a VARI process molding simulation has been carried out on a curved plate and a ribs reinforced plate of foam sandwich structural composite by using PAM-RTM software. The simnlation is verified by the vacuum-assisted resin infusion molding experiments.