A hidden concrete column was built at the core of the T-shaped joints composed of plaster-concrete compound panels in order to study their earthquake resistant behavior. In this paper, earthquake resistance tests were performed on two types of composite T-shaped joints, six samples in total, in which the horizontal steel bars were embedded and not embedded in their core, to analyze the mechanical deformation, cracking, hysteretic behavior, ductility, and stiffness degeneration of the composite T-shaped joints as well as their energy dissipation properties such as damping coefficient, energy dissipation coefficient, and power ratio coefficient. The two types of composite joints composed of interior and exterior compound walls were found to have good mechanical properties. A comparison of the various indicators for the two types of T-shaped joints revealed that embedding the horizontal steel bars embedded in the web and flange of the T-shaped joints in their core can help improve the earthquake resistance and energy dissipation properties of the composite T-shaped joints.