A quantitative shear wave elasticity imaging method and system relates to the technical field of medical ultrasound imaging. The provided ultrasound quantitative elasticity imaging method and system are based on a sliding window linear fitting strain and use a two-dimensional linear fitting shear wave velocity detection algorithm, and thus, the anti-noise capability is stronger, and the result is more reliable. Moreover, where the load of an ultrasonic front-end storage and transmission module is not additionally in-creased, global ultrasonic quantitative elasticity imaging is realized, thereby significantly reducing the design difficulty of the ultrasound quantitative elasticity imaging system and the device cost.