The invention relates to a water filter with a double sterilization function. The water filter comprises a filter element shell and a replaceable inner core assembly. The filter element shell comprises a shell body. A water inlet is formed in the upper end of the shell body, and a strengthening die block is arranged at the upper portion of the shell body and made of graphene, and the graphene is packed through a dialysis bag to be prevented from leaking. A plurality of water outlet holes are formed in the lower end of the shell body, and the inner core assembly is arranged in the shell body. The inner core assembly comprises a core tube which is through vertically, and the core tube is filled with padding. Upper-layer nano-silver filtering cloth is arranged at the upper end of the core tube, lower-layer nano-silver filtering cloth is arranged at the lower end of the core tube, and the upper-layer nano-silver filtering cloth and the lower-layer nano-silver filtering cloth are used for limiting the padding into the core tube. Nano-silver on the nano-silver filtering cloth can be used for achieving first-level sterilization and achieving lasting sterilization; active carbon and ion exchange resin in the padding are used for achieving the functions of softening water, removing heavy metal and adsorbing pesticides and residual chlorine.