Abstract: The accelerated aging test in lab and natural exposure test on ship in the marine environment for G827/3234 composite were carried out.By using the universal testing machine, optical microscope, SEM, DMA, FTIR and so on, the surface and fracture morphology, mechanical property and composition of G827/3234 composite were observed and measured before and after aging.The regression analysis method for the strength median curve of G827/3234 under the natural aging condition was improved, and the equivalent accelerated relationship between the accelerated aging and natural aging was obtained based on the strength retention rate and it was verified. The results show that, after one month of accelerated aging, the flexural strength and flexural modulus of G827/3234 composite are decreased by 1.43% and 4.45%, the decline of interlaminar shear strength is 8.80%, the anti-fatigue property is essentially the same, the glass transition temperature is decreased by 6.2℃, the in ternal friction increases and the storage modulus is decreased by about 5 GPa.The mechanism in the accelerated aging and the strength median equation in the natural aging under the marine environment are given out.The equivalent coefficient of accelerated aging to natural aging is 4.52.The aging mechanism of the two are basically the same and the coefficient is proved to be effective and available.