Abstract: For the shortcomings of difficult modeling and large simulation calculation in VARI process molding simulation of large size or complex shapes sandwich structure composites with traditional refined modeling method,this paper proposes a simple and convenient equivalent modeling method in which a VARI process molding simulation has been carried out for a rectangular plate of foam sandwich structural composite by using PAM-RTM.The equi-va-lent modeling simulation is verified by the vacuum-assisted resin infusion molding experiments,also the density,resin content and mechanical properties have been tested and characterized.The results show that the theoretical resin filling time obtained from simulation deviates little from the filling time measured in the molding experiments.The curves of resin flows forward position getted from equivalent modeling is consistent to the test value in the actual process molding,and VARI molding process has certain influence on the uniformity of properties distribution of sandwich structural composites.