The utility model relates to a CT (Current Transformer) live-line test box. The CT live-line test box comprises a box body, a box cover, a pressure plate type connecting piece, a CT tap wiring column, a ground wiring column, a knife switch and a fuse, wherein the box cover is arranged on the upper end of the box body and hinged with the box body; the pressure plate type connecting piece, the CT tap wiring column, the ground wiring column, the knife switch and the fuse are arranged inside the box body; the pressure plate type connecting piece and the fuse are mutually connected; and a wire inlet hole is arranged at the side wall of the box body. According to the CT live-line test box provided by the utility model, the CT tap is led into the CT live-line test box through a shielding wire from a secondary terminal interface place; through three-stage protection of the knife switch, the pressure plate type connecting piece and the fuse, safety of in-situ test can be greatly enhanced; in the process of CT live-line test, due to the existence of the fuse (breakdown and ground connection are carried out as soon as the voltage is more than 250V), open circuit of the end screen can be prevented, strong support and guarantee are provided for safely and quickly completing the CT live-line test work, and the CT live-line test box is provided with a broad promotion prospect.