To reveal the interfacial bond behavior between square steel tube and recycled aggregate concrete （RAC）after exposure to high temperatures，a push-out test of 20 specimens after exposure to high temperatures was designed and completed by considering two parameters including the maximum temperature（T）and the replacement percentage（γ）. The failure process and morphology of the specimens were observed，the load-slip curves of the loading end and the free end were obtained，and the influence laws of test parameters on the interfacial bond behav? ior and the bond damage process were analyzed. The regression bond strength formulas and bond-slip constitutive equations of RAC-filled square steel tube（RACFSST）subjected to high temperatures were proposed. The results show that the curves shape at the loading end and the free end are similar，but the initial slip at the loading end devel? ops earlier. The shape of the load-slip curves can be divided into two types according to the maximum temperature（i. e.，T≤200 ℃ and T≥400 ℃）. The interfacial bond behavior of RACFSST is worse than CFSST（The average differ? ence of the corresponding bonding behavior is about 3.10% to 19.05%）. With the increase of T，the bond strength and the bond shear stiffness decrease at first and then increase，and the energy dissipation capacity of the interface in? creases gradually. With the increase of γ，the bond strength decreases gradually. Moreover，the bond shear stiffness and the energy dissipation capacity of the interface show the law of first increase，then decrease and then recovering slightly with the increase of γ. The initial bond damage of the interface is delayed at 600 ℃，and it tends to be earlier with the increase of γ. However，the influence of T and γ on it is not obvious at T≤400 ℃. The development speed of bond damage increases first and then decreases with the increase of T and γ.