The invention relates to a three-shock-excitation-motor elliptical vibrating screen based on elastic coupling. The three-shock-excitation-motor elliptical vibrating screens based on the elastic coupling is mainly composed of a first shock excitation motor, a second shock excitation motor, a third shock excitation motor, a connecting rod, sliding grooves, a motor base, a screen box, sliding blocks, springs and the like. The motor base is fixed to a side plate of the screen box, and the three shock excitation motors are connected to the motor base through bolts. A sliding groove is welded to each of the two ends of the connecting rod, and the sliding grooves are parallel to each other. The second shock excitation motor and the third shock excitation motor are installed with axes parallel, the second shock excitation motor and the third shock excitation motor rotate in the same direction, and sliding blocks capable of rotating relative to eccentric blocks are installed at the positions with same radious vector on the same-side eccentric blocks of the second shock excitation motor and the third shock excitation motor. A shock excitation inertia force generated by the first shock excitation motor is also a circular exciting force, the circumferential changing direction of the shock excitation inertia force is opposite to that of a circular exciting force combined by the second shock excitation motor and the third shock excitation motor, and the shock excitation inertia force and the circular exciting force are combined to an elliptical exciting force with the center fixed. According to the three-shock-excitation-motor elliptical vibrating screen based on the elastic coupling, the exciting forces of the three shock excitation motors can be brought into play to achieve the maximization of a general exciting force, the structure is simple, the installation is easy, the noise is low, and the cost is low.