Abstract: The present invention discloses an improved expansion card slot structure including a slot base with a plurality of rear-end fixing pins, and a shield bracket installed at the slot base for shielding a rear-end port of the slot base and allowing a plurality of contact portions of the shield bracket to be in contact respectively with an upper end of each rear-end fixing pin, and a plurality of elastic arms to be in contact respectively with a main body portion of each rear-end fixing pin and disposed proximate to a lower end of each rear-end fixing pin. With this structure, the invention increases the number of electromagnetic interference (EMI) contact points and provides a shorter path for grounding and eliminating noises to improve the electromagnetic interference (EMI) effect.