The invention relates to a digital output channel self-checking system based on an FPGA. The digital output channel self-checking system comprises an FPGA and a plurality of digital output channels. Each channel comprise a photoelectric isolator, a drive switch tube and a loopback acquisition circuit; the FPGA works as a main processor to be in communication with a host computer, transmitting and receiving of commands and data are achieved, and control and self-checking logic of each channel are achieved; electric isolation of output from a control signal is achieved via the photoelectric isolator; drive of output points is achieved via the drive switch tube; the loopback acquisition circuit is used for loopback acquisition of the output signal for self diagnosis; and the drive switch tube is connected to the loopback acquisition circuit, and the FPGA is connected to the drive switch tube and the loopback acquisition circuit via the photoelectric isolators, and a self-checking channel is formed. The digital output channel self-checking system and method are advantageous in that, in normal output, whether a normal overturn for a channel is diagnosed, and channel faults are diagnosed in advance.