A high-speed connector assembly, a socket connector and a grounding plate are disclosed in the present invention. The grounding plate disposes multiple grounding arms and multiple shielding pieces, which are arranged in a serpentine pattern for surrounding front mating portions of each pair of differential signal socket terminals to be in a U-shaped state, thereby providing electromagnetic shielding. The grounding plate further disposes multiple spring fingers, which can be used to connect adjacent grounding plates for forming a common grounding path, and further reducing signal crosstalk of adjacent differential pairs. The grounding plate of the present invention can further contact with a corresponding shielding shell of a plug connector to form a complete grounding path, and ensure more stable and reliable signal transmission quality.