Under extreme services conditions, the dynamic mechanical properties of polymer matrix composites play an important role in controlling the durability of composite structures. Temperature-frequency-dependent dynamic mechanical properties of glass/epoxy composites were studied under different loading modes by dynamic mechanical analysis. The temperature-dependent modulus and temperature-frequency-dependent modulus models of epoxy resin and glass/epoxy composites were developed. The physical meaning and how to determine the values of parameters in the model were discussed. All the model predictions showed good agreements with the experimental results.