The utility model relates to the technical field of power electronics and discloses water cooling plates for a transformer. Each water cooling plate for the transformer comprises a plate-shaped plate base body; two flexural ditches are formed in at least one side of the plate base body, respectively a first ditch and a second ditch, wherein the cross sections of the second ditches are both shaped like a half circular arc. A plurality of the water cooling plates for the transformer, disclosed by the utility model, can be rapidly spliced into a water cooling module and randomly arranged between two adjacent coils or between a coil and an iron core. The ditches in two adjacent plate base bodies can form a circulating water passage for circulating water to flow, so that the coil or the iron core on the outer side can be cooled. Besides, the ditches of the water cooling plates disclosed by the utility model are bent and the cross sections are shaped like a half circular arc, so the contact area between cooling water and the plate base bodies can be increased and the water cooling effect can be improved.