The invention, which belongs to the key technology of the intelligent device, discloses a device and method for checking broadband frequency characteristics of a direct-current current transformer. The checking device is composed of a clock synchronization device, a message parsing device, a high-speed acquisition card, and a digital checking system. The digital checking system receives discrete sampling data of the message parsing device and the high-speed acquisition card; a broadband error and a steady-state error result of a direct-current transformer are calculated based on the discrete sampling data in a digital quantity checking mode; the digital checking system receives the discrete sampling data outputted by the high-speed acquisition card and a broadband error and a steady-stateerror result of the direct-current current transformer are calculated based on the discrete sampling data in an analog quantity checking mode. According to the invention, the broadband characteristicchecking and the steady-state error checking functions of the direct-current current transformer with the analog signal output and digital signal output are realized; the broadband error of the direct-current current transformer can be measured accurately; and a technical means is provided for accurate calibration of the broadband frequency measurement characteristic of the direct-current currenttransformer.