The invention relates to the technical field of assembling of a vibration motor, and discloses an iron core vibration motor rotor assembling tool. The assembling tool comprises a base plate, a side plate is arranged on the base plate, a side surface of the side plate is provided with a horizontal baffle, the inner side surface of the baffle is fixedly connected with the side plate, an outer side surface of the baffle extends to form a support plate, edges of the outside of the support plate are provided with a plurality of positioning gaps, a side surface at the upper end of the side plate is provided with an elevating cylinder, and a shaft end of the elevating cylinder is provided with a pressure plate parallel to the baffle. The beneficial effects of the assembling tool are that the assembling efficiency is high, and the assembling precision can be accurately controlled.