A terminal plate set and an electric connector including the terminal plate set are disclosed. The terminal plate set includes two signal terminal plates and two grounding terminal plates, and the signal terminal plates are parallel to each other and disposed between the grounding terminal plates. A partition channel is formed between the grounding terminal plates, between the signal terminal plates, between the signal terminal plate and the grounding terminal plate, or between the terminal plates. The electric connector includes the terminal plate set and a front body, and the terminal plate set is installed at the front body, and a front convection hole is formed on a plug side of the front body. The impedance of the signal terminal plates and the grounding terminal plates can be adjusted within the best range to improve the heat dissipation efficiency of the terminal plate set and the electric connector.