The prediction of dynamic stress-strain relationship of composite geomembrane is one of the key problems involved in the long-term operation of seepage prevention projects of earth-rock dams. In order to study the effect of cyclic loading on the stress and strain of the composite geomembrane, cyclic loading and unloading tests were carried out under three different stress levels of 10%, 20% and 30%, and the creep tests under 10% to 80% stress levels were carried out to compare and analyze the creep and creep recovery characteristics of the composite geomembrane. The expression of strain under cyclic loading and accumulation condition was presented, and the constitutive model of composite geomembrane boundary surface under cyclic loading condition was constructed. The results show that the deformation of composite geomembrane increases instantaneously at the moment of loading and unloading, and then gradually slows down with the increase of time. After complete unloading, when the stress level is less than 30%, the deformation of the composite geomembrane can almost recover. When the stress level is greater than or equal to 40%, the residual deformation increases gradually with the increase of the stress level. The effect of cyclic loading times on the creep deformation of geomembrane is not a simple linear relationship. In addition, an improved three-parameter viscoelastic model was established, and it is verified that the model can reproduce the creep recovery process of composite geomembrane under different load levels. The research results can provide a reference for the long-term deformation analysis of composite geomembrane in earth-rock dams.