Abstract: The present application is relate to a method and system for treating high salinity water, comprising the following steps: step 1, by a first membrane concentration unit, concentrating the raw water; step 2, with the assistance of a crystallization initiation unit, mixing the raw water concentrated, initiating crystallization by a seed crystal, and, discharging precipitated crystals; step 3, with the assistance of a crystallization termination unit, firstly, introducing the resulting water of the crystallization initiation unit, then, terminating crystallization, secondly, discharging precipitated miscellaneous salts; step 4, with the assistance of a mechanical filter unit, the liquid to discharged from the crystallization termination unit flowing through the mechanical filter unit, removing the residual seed crystal and floccules; step 6, with the assistance of a second membrane concentration unit, the concentrated salinity water entering the second membrane concentration unit for concentration.