Tension measurement of geogrid is essential in reinforcement mechanisms studies. Geogrid is a nonlinear flexible material with large apertures, it is difficult to measure the tensions mobilized in geogrid, especially in scaled-down geogrid in centrifuge modeling. In this study, strain gauges were glued onto the surface of model geogrid with epoxy resin and were calibrated through multi-stage and continuous tensile tests. Generalized Kelvin model was used to fit the constitutive curves from the tensile tests. The model is capable to describe time-dependent and nonlinear behavior of the composite material of epoxy resin and model geogrid. Based on generalized Kelvin model, tensions in the model geogrid were measured in a centrifugal modeling of a reinforced embankment on soft clay. A finite element model was developed to simulate the centrifuge modeling and a comparison was carried out between the computed and measured tensions. The numerical results basically captured the measured reinforcements, indicating that the method of reinforcement measurement proposed in this study is appropriate and reasonable.