Full-duplex is a technology in telecommunication domain that can perform transmitting and receiving at the same time and in the same frequency band. The major obstacle of full-duplex is the self-interference (SI). Some previous works have focused on the SI cancellation in radio frequency (RF), and generally on a narrowband signal model. We have implemented a full-duplex prototype with orthogonal frequency-division multiplexing (OFDM) technology on GNURadio and Universal Software Radio Peripherals (USRP). We focus on the baseband, namely the digital part of the SI cancellation. Our testbed can achieve a digital cancellation of 27dB. After the cancellation, the signal of interest can achieve a bit error rate (BER) in the scale of 105 at 4 meters, which is very close to the performance of half-duplex. This is, to our knowledge, the first full duplex implementation for OFDM technology.