Steel/CFRP double-strap joints adhesive-bonded by epoxy were tested in tension under different temperatures ranging between 20°C and 60°C. Effective bond length was experimentally determined at 20°C first. Specimens, varied with the effective, half and twice the effective bond length and with one or three carbon fibre layers, were examined under the specified temperature range. It was found that the ultimate load and the joint stiffness of all specimens decreased significantly at temperatures near to Tg. Based on the kinetic modeling of glass transition of adhesive, a mechanism-based model was proposed to describe the strength and stiffness degradation of steel/CFRP double strap joints at elevated temperatures, and the modeling results were validated by the corresponding experimental measurements. In addition, it demonstrated that the effec-tive bond length is increased with temperature.