Abstract: At present, there is no simplified method to study the mechanical and deformation characteristics of asphalt concrete core. Aiming at the serious tensile phenomenon of high asphalt concrete core, the mechanism of the core producing tensile stress is analyzed. The concept of reducing the tensile stress of the core is proposed. The rockfill dam with straight core is designed to be the rockfill dam with curved core combining with the special transmission mechanism of the arch structure. Based on the theory of Winkler elastic foundation straight beam and curved beam, the simplified mechanical analysis model for the straight core and curved core is established. The influences of the dam height and rockfill modulus on the deflection and tensile stress (bending moment) of the straight core are investigated. The effect of the curved core to reduce tensile stress is also investigated. The results show that the simplified mechanical analysis model can reflect the force and deformation characteristics of the core. And there exists large tensile stress at the end of the straight core. The higher the dam height and the smaller the rockfill modulus, the greater the tensile stress at the end of the core and the greater the risk of the core-producing tensile failure. The curved core shortens the axis with the help of deflection and transforms the lateral load into axial compression load to reduce the bending moment and increases the axial force to reduce the tensile stress at its end. Compared with the straight core, the curved core can reduce the tensile stress about 42.5% at its end, which can greatly improve the mechanical characteristics and increase the security of the core.