The utility model relates to an integral circular electrical connector. The electrical connector is characterized in that an O-shaped ring (205) for matched sealing is arranged between a socket (2) and a plug (1), wherein the O-shaped ring is a silicon rubber O-shaped ring in the specification of 20*2.4mm; the integral circular electrical connector employs a compression joint contact; and the plug (1) is connected with the socket (2) via rectangular threads, wherein specific requirements of the rectangular threads include that the pitch is 10mm, the pitch height is 5mm, and the helical angle is 15.7 DEG. The integral circular electrical connector completely satisfy technical requirements of NFF61-030 standard, which can be applied to high-speed locomotive, subway and light rail projects, and is characterized by high mechanical intensity and good environment resistance; mis-plugging resistance can be realized by key position shifting; and the integral circular electrical connector is especially suitable for electrical connection between a compartment and another compartment or a chassis and a control cabinet, and possesses great economical and social values.