Abstract: Because of the good performances such as high spectrum efficiency, strong abilities of anti-multipath and anti-impulse noise, high-speed transmission capacity under efficient bandwidth utilization and simple implementation, OFDM becomes one of the research priorities and hotspots in underwater acoustic communication. Underwater acoustic real-time communication is realized on the TMS320C6455DSK(DSP Starter Kit) based on the study of OFDM. The Songhua river trial got the following results: the data rate is 1873bps and the bit error rate less than 10^-4 for the underwater acoustic communication with QPSK modulation, rate-1/2 channel coding, and signal frequency between 4kHz and 8kHz at the distance of 4.3km.