Abstract: A multi-band antenna and a terminal device, where the multi-band antenna includes a feeding part connected to a capacitor component to form a feeding circuit, and a feeding matching circuit is electrically connected between a feeding radio frequency circuit and the feeding circuit, a radiation part is electrically connected both to the feeding circuit and a grounding part, the grounding part is electrically connected to a ground plane, a first resonant circuit is formed from the feeding circuit to an end that is of the radiation part and that is away from the grounding part, and the first resonant circuit generates a first resonance frequency and a second resonance frequency.