The article presents results of study possibility of hardening of high-manganese steel X120Mn12 by a deformation wave in the process of wave strain hardening (WSH). Features of the method is possibility of using shock waves for plastic deformation, which significantly expands the technological capabilities for formation of a hardened surface layer. The dominant design and technological parameters of the hardening treatment are established, which have the main influence on the microstructure and hardness of the hardened surface layer. Possibility of a significant increase in hardness and depth of hardened surface layer is established. The depth of hardened layer can reach 6-8 mm, and the hardness can be increased by more than three times. Microstructural analysis showed no cracks. The obtained results of conducted research can be used to develop a technology for strengthening the deformation wave of various heavy-loaded parts made of high-manganese steel.