To study the effect of high temperature on the dynamic bonding performance of reinforcement concrete, a three-dimensional mesoscale model considering the surface characteristics of deformed reinforcement and the heterogeneity of concrete was established. Compared with the experimental failure pattern and bond stress-slip curve, the rationality of the mesoscale model was verified. On this basis, the variation of dynamic bond-slip behavior of reinforcement concrete at high temperature or after cooling down was analyzed. Combined with the numerical simulation results, a dynamic bond strength prediction equation considering the high temperature effect was developed. The results show that: (1) the mesoscopic model can reflect the cracking process and bonding failure mechanism of the interface between deformed reinforcement and concrete; (2) with the increase of strain rate, the damage area of concrete at high temperature or after cooling down decreases gradually. At the strain rate, the damage area of concrete at high temperature is significantly larger than that after cooling down; (3) with the increase of temperature, the ultimate bond strength decreases linearly at high temperature or after cooling down; (4) at the same temperature, the increase of strain rate makes the ultimate bond strength increase nonlinearly; (5) the good agreement between the predicted results and the experimental results indicates that the empirical formulae presented in this work can reasonably reflect the high temperature effect on the dynamic ultimate bond strength between reinforcement and concrete.