The invention discloses a method and system for ultrasonic detection of cornea viscoelasticity. The method comprises the following steps of firstly, focusing sound waves with certain power onto a cornea to generate a sound radiant force on the cornea; under the action of the sound radiant force, the cornea generating slight vibration, and the vibration propagating outwards in the cornea in a Lamb wave way; then, transmitting a detection pulse to an eyeball, the pulse reflecting in the tissues of the eyeball to form echo, and receiving the echo; and finally, extracting the vibration information of the cornea from the echo, and according to a certain mathematical model, obtaining an elastic module and a viscosity coefficient of the cornea. The elastic module and the viscosity coefficient can be simultaneously and quantitatively measured, and mechanical properties of the cornea are fully described. Meanwhile, the system has the advantages that the structure is simple, easy implementation is realized, the cost is low, and the like. The system can be used as independent equipment, and also can be used as an additional function module to be loaded onto the existing color ultrasonic system for use, so the market population prospect is better.