Abstract: The experiments of five joints of both steel-encased high-strength concrete column and high-strength reinforced concrete beam without steel-encased were carried out under cyclically reversed loading. Analyzing the horizontal shearing force distribution in joint core area, the calculation of such shearing force was discussed, as well as the shear stiffness conditions of the high-strength concrete, steel section web and hoopings in joint core area. The results indicate that the crack resistance of the section doesn't increase but the shear stiffness of joints increases greatly. The inflexion point on the loading-displacement curve is not found obviously because the steel section is encased in the high-strength concrete. The shear stiffness of joints is provided by that of concrete, section web and hoopings, among which the high-strength concrete is the predominant one.