The invention relates to a shielding piece of a back panel connector. The shielding piece comprises a shielding piece body, wherein the shielding piece body is arranged at an upper side or a lower side of a differential pair installation plate, an avoidance hole is formed in the shielding piece body and is used for avoiding a differential pair, and a contact part is further arranged on the shielding piece body and is used for being contacted and connected with each grounding pin on the differential pair installation plate. By forming the avoidance hole in the shielding piece body, the corresponding differential pair is annularly shielded; meanwhile, by arranging the contact part, used for being contacted with the grounding pin to achieve shielding connection of each grounding pin, on the shielding piece body, all grounding pins can be connected in series, the shortest signal return path is provided for an encircled signal, resonance is moved backwards within frequency domain, and larger transmission bandwidth is provided.