A terminal structure includes ground terminals, signal terminals, connection elements, and ground electrical connection elements. The connection elements connect the ground terminals to the signal terminals, respectively. The ground electrical connection elements are in connection with connection elements and in electrical contact with at least a ground terminal. An electrical connector includes two terminal structures and a casing. The connection elements are connected to each other. An insertion slot is disposed on the front side of the casing. The terminal structure is disposed at the casing. The resilient ground electrical contact segments and the resilient signal electrical contact segments face the insertion slot. The ends of the ground electrical connection segments and the ends of the signal electrical connection segments are exposed from the casing. The terminal structure and the electrical connector improve resonance, adjust impedance, reduce signal loss, simplify die structures, and extend service life of a die.