An embodiment of the invention provides a novel high-accuracy current transformer suitable for a GIS, belonging to the technical field of precise measurement of current. The GIS comprises at least onecurrent-carrying conductor and a protective shell, and the current transformer comprises multiple quantum sensors, and a quantum detection system, wherein the quantum sensor is used for measuring magnetic field strength around each current-carrying conductor, at least 4n quantum sensors are uniformly distributed on a virtual circle with a central axis of each current-carrying conductor as a center of a circle and preset length as radius, a magnetic shielding layer is arranged at the periphery of each virtual circle, wherein n is a positive integer, and the quantum detection system is connected with each quantum sensor, and is used for acquiring magnetic field strength around the current-carrying conductor through the quantum sensor, and calculating current of each current-carrying conductor according to the magnetic field strength.