Six specimens of interior joints with different depth beams were tested under reversed cyclic loading. The failure characteristics and shear force versus shear angle skeleton curves of interior joints are analyzed. Based on the experimental study, an analytical model for equivalent joint core of abnormal joint under the combined action of axial load and shear is established, and the shear stress versus shear angle curves of equivalent joint core of tested specimens was calculated by using modified compression field theory (MCFT).Test results indicated that the first crack appeared in the minor core (determined by the low beam and the top column), and the final failure appeared in the large core (determined by the high beam and the bottom column). The critical crack load was quite nearly with the ultimate load of abnormal joints, and seismic behavior of beam-column joint sub-assemblage was poorer than that of ordinary joints. Good agreement between experimental results and prediction results is achieved.