Abstract: A novel electromagnetic shunt tuned mass-inerter damper (EM-TMID) is proposed, which can realize dual functions of both vibration suppression and energy harvesting. A novel feature of the damper is that the viscous damping of traditional tuned mass dampers is replaced by that of electromagnetic transducers with inertance. According to the Alembert's theorem, the dynamic model of a coupled EM-TMID and a single degree of freedom structural system under seismic excitation is established. Based on the H₂ norm method with the aim of minimizing the root mean square value of the damage to the main structure, solutions of the three parameters, that is, the mechanical tuning ratio, electrical damping ratio and electromagnetic mechanical coupling coefficient, are obtained. With the optimal parameters, the frequency-domain and time-domain numerical simulations of the EM-TMID are conducted to analyze the dual functions of the vibration suppression and energy harvesting. The results show that in the frequency domain, the EM-TMID is superior to the classical TMD, EM-TMD and TMDI in terms of the reduction of the peak and area of the frequency response of the displacement of the main structure. In the time domain, the EM-TMID is superior to classical TMDs in terms of the reduction of the peak and root mean square value of displacement and acceleration. Meanwhile, the EM-TMID can also harvest energy.