The utility model relates to the sewing machine field, and aims to provide a sewing machine motor rotor iron core. The sewing machine motor rotor iron core is formed by laminating the silicon steel sheets at the out circumferences of which the uniform slots are punched, the slots of the laminated silicon steel sheets are connected to form the guide strip grooves, and an included angle alpha exists between the length directions of the guide strip grooves and the axis of the sewing machine motor rotor iron core. The recess sets consisting of a plurality of positioning recesses evenly distributed along the circumference are arranged on the front end faces of the silicon steel sheets, and the bump sets consisting of a plurality of positioning bumps of which the number is same as the number of the positioning recesses and shapes match the positioning recesses are arranged on the back end faces of the silicon steel sheets. For every two adjacent silicon steel sheets, a difference angle beta exists between the positions of the recess set and the bump set of the first silicon steel sheet located at the front side and the positions of the recess set and the bump set of the second silicon steel sheet located at the back side. The sewing machine motor rotor iron core is convenient in lamination operation and stable in lamination quality.