A detector system for a CT scanner is provided. The detector system may include a plurality of detector modules. Each of the detector modules may include a supporting frame, two or more detectors and an interface board. A supporting frame may be connected to a casing of the detector system. Detectors may be mounted onto a supporting frame and may convert an X-ray beam within a CT scanner into an electrical signal. An interface board may be disposed in an outer side of a supporting frame away from the focus of an X-ray tube, and may be electrically connected to a plurality of detectors through a connector, so as to provide a control signal and a power supply to the detectors, and to transmit a digital signal outputted by the detectors to a backplane of the detector system through an output line.