A detector module is provided, where a side of a signal adapter circuit board opposite to an X-ray source has an analog signal output terminal, at least one A/D chip is installed on an A/D conversion circuit board, and the signal adapter circuit board and the A/D conversion circuit board are connected through non-removable flexible connection with a data line. The data line is connected with the analog signal output terminal and an input terminal of the at least one A/D chip, and is adapted to transmit an analog signal. Therefore, the number of A/D conversion circuit boards in a direction of a channel of a scan chamber is increased, and a signal adapter circuit board along a direction of the channel of the scan chamber may be set to have a maximum width when detector modules are arranged closely, which is beneficial for reducing wiring density of signal wires.