Abstract: A new structure of resonant vibrating machinery with dual-motor drives is proposed. The vibrating body consists of a supporting rigid frame and a material box. The material box exhibits four degrees of freedom and the rigid frame exhibits only one degree of freedom in the resonant direction. The material box is installed on a plane perpendicular to the resonant direction by soft springs. The material box not only moves together with the rigid frame, but also exhibits two translational degrees and one rotational degree of freedom and operates at the super-resonant state. The vibration amplitude increases with increasing amount of material. Motion equations for the vibrating system are established by using the Lagrange's equation. The conditions of synchronization and stability are deduced. The relation between the coefficient of synchronization ability and the structural parameters of the system is also studied by numerical computation. The results demonstrate that the smaller the distance between the two unbalanced rotors and the smaller the resonant exciting angle, the greater the coefficient of synchronization ability is. The ratio of the mass of the material box to that of the vibrating system affects little on the coefficient of synchronization.