Abstract: To investigate the effect of different environment and stress levels on creep of glass fiber reinforced polymer composite ( GFRP) ，its creeps under the effect of atmospheric and chloride ion environment during different test periods were measured． The results showed that the rate of creep increases fast initially and slower in late period． The property of GFRP was influenced by environment and stress level， in the same environment， the higher stress level， the more increment of creep; in the same stress level，the increment of creep of GFRP in chloride ion was higher than that in atmosphere; water absorption and diffusion in the resin resulted in a volumetric expansion leading to microcracks， and then decreased the properties of it's viscoelasticity． There was a chemical reaction of the resin with the water molecules， and the chemical agents were easily leached out，which led to the occurrence of pits， then the bonding between the fiber and the matrix broke． The creep prediction model of GFRP and its applicability were proposed， based on the standard linear solid model theory by Kelvin，considering various environment and stress range．