The invention relates to an ultralow disturbance torque rotating shaft system which comprises a main shaft. The upper end of the main shaft is connected with a working table face, the main shaft penetrates a gas bearing, the main shaft and a gas bearing are coaxially installed, the lower end of the main shaft is connected with a brushless torque motor, an electric conduction sliding ring is arranged below the main shaft, and a sliding ring servo system is arranged below the electric conduction sliding ring. The sliding ring servo system comprises the electric conduction sliding ring, a siliconphotocell, a silicon photocell detecting plate, a sliding ring servo motor and a sliding ring shaft; the electric conduction sliding ring is composed of a rotor and a stator, the main shaft and the rotor are coaxially installed without contact, the lower end of the main shaft is connected with an additional weight, the electric conduction sliding ring is arranged below the additional weight and is not in contact with the additional weight, the stator of the electric conduction sliding ring is connected with a sliding ring shaft, and the sliding ring servo motor and the sliding ring shaft arecoaxially installed; the silicon photocell detecting plate is installed on the lower end face of the additional weight, and the silicon photocell is installed at the position, corresponding to the silicon photocell detecting plate, of the stator of the electric conduction sliding ring; and the rotor of the electric conduction sliding ring is connected with the working table face of a rotary tablethrough a flexible cable and rotates together with the working table face.