Crack sealing with hot-applied sealant is a widely used technology for asphalt pavement crack repair, but the sealant usually occurs bond failure at an early stage. Due to the research on the mechanical changing characteristics of crack sealant bonding interface is insufficient, the systematic analysis and explanation for the early failure phenomenon is lack. Based on this, a 3D finite element (FE) model of asphalt pavement with crack repair structure is established to study the dynamic behavior characteristic of crack sealant. Firstly, the dynamic response characteristics of the crack sealant bonding interface under different repair groove sizes and forms are systematically analyzed. Then the recommended repair groove size range is given accordingly. Secondly, the effects of different vehicle speeds and axle loads on the dynamic response of the crack sealant bonding interface are analyzed. The results show that lower vehicle speeds and higher axle loads result in higher stress levels at the crack sealant bonding interface, the sensitivity of tensile stress to vehicle speed and axle load is higher than that of shear stress. Finally, the temperature stress field of the repair structure is used as a predefined field and imported into the 3D FE model. The dynamic response of crack sealant bonding interface under thermal-mechanical coupling is analyzed. The results show that the tensile stress of bonding interface is mainly affected by temperature conditions, and the vehicle load is the primary factor affecting the level of shear stress. The research findings provide a scientific insights and guidance for the evaluation of crack sealant performance and the improvement of crack repair technology. •The recommended repair groove size range was given.•The influence of thermal-mechanical coupling was evaluated.