Abstract: The purpose of this research is to investigate properties of the glass fiber reinforced composites under the water environment.VARI(vacuum assisted resin infusion) technique was employed to fabricate 2 and 3 layers laminates of glass fibre reinforced unsaturated polyester.Samples were immerged in distilled water for a certain period of time,and the tensile and bending properties of the composites were measured.The microphotographs of the cross sections of the composites before and after immersion in the water were shown in the paper and corresponding analysis was made.It is revealed that the tensile strength was declined with the increase of water immersion time,meanwhile,the bending strength showed a descending trend.