Electromagnetic riveting (EMR) technology can effectively form large-diameter rivets in a single process and quickly produce high-quality joints. It has broad application scenarios in the aerospace industry, but there are few studies related to EMR joints for large-diameter steel rivets. In this paper, an EMR platform for large diameter rivets was built, and the riveting process test was carried out for 10 mm diameter steel rivets. The results show that the header diameter increased with increasing discharge energy and the header height decreased with increasing discharge energy. At the same discharge energy, the larger the preformed hole diameter, the smaller the header height and the larger the header diameter. In addition, the interference fit size of riveted joints gradually increased with the increase of discharge energy for both prefabricated hole diameters. The interference fit size of riveted joint with the prefabricated hole diameter 10.1 mm was always greater than that with 10.3 mm. At the same time, the value (10.3 mm) was not suitable as the preferred process parameter because the riveted joint with the prefabricated hole diameter 10.3 mm tended to be skewed during the riveting process. In addition, the optimal process parameters were obtained by combining the discharge energy: the prefabricated hole diameter of 10.1 mm and the discharge energy of 15.5 kJ. Finally, the interference fit size and mechanical properties of the EMR joints were compared with those of the conventional hydraulic riveted joints. The results indicated that the interference fit size (2.15%) of the EMR joint prepared according to the optimal process parameters was larger and more uniform than that of the hydraulic riveted joint (1.75%). The maximum shear load and energy absorption values were slightly higher than those of the hydraulic riveted joint.