Abstract: Geogrid is applied widely in soil reinforcement engineering. There is a complex coupling effect between the elastic deformation of geogrid and soil creep. Through theoretical analysis and field test, the coupling effect model of geogrid elastic deformation and soil creep is established, and the constitutive equation as well as the creep equation are deduced. Through field test and theoretical calculation, it is concluded that the stress level of soil has little effect on the strain stability time, but has a great influence on the strain rate and strain stability value. The viscosity coefficient of soil has a great influence on the strain rate and strain stability time, but has little influence on the strain stability value.