The invention provides a magnetic steel blank forming device. According to the magnetic steel blanket forming device, magnetic steel powder is shaped by adopting a shell; while pressing is carried outthrough a pressing plate, the powder is preheated through electric heating so that the powder and the shell can be preliminarily combined; an annular ring at the bottom of the shell is located in a circular supporting groove, and due to the fact that the contact area is small, a part of the powder can be leaked out so that the effect that the magnetism of a product can be influenced because the powder is pressed too tightly can be avoided; the powder can be loaded into the shell repeatedly until the pressing combining state of the powder meets a requirement; and finally, the shell and the powder are put into a sintering device for sintering treatment so that the magnetism of the interior of a magnetic steel can be guaranteed, and meanwhile, the purpose of firmness of the exterior can be achieved.