In this paper experimental processes are carried on to investigate the effects of resin viscosity and pressure on infiltrated heights and qualities of RFI composites.The results show that totally a higher viscosity will decrease the height of infiltration.Depending upon the resins of various viscosities and pretreatment of fabrics,the pressure leads two different effects on driving pressure of resin infusion and the compaction of fiber bed to decrease its permeability.Higher pressure always improves the quality of infiltration and lower void content.Analysis also shows that actually the influence of pressure on infiltration height is the results of cooperation of infiltrate pressure and compaction of fiber bed.