Abstract: In this paper, based on frequency shift keying (FSK) coherent demodulation technology, a low-power consumption and high-reliability underwater acoustic remote control system is designed. The transmitter transmits 50 kHz and 60 kHz signals as encoded signals, and the receiver uses a high Q-value LC frequency-selective amplification circuit as the pre-amplifier, which can effectively suppress out-of-band noise. The received signal undergoes coherent demodulation to obtain the coded signal. The signal is sampled by a dual-channel AD converter, and the difference is calculated to obtain the coding information. By using this method, the demodulation error rate can be effectively reduced, and communication reliability can be improved. The underwater acoustic communication channel is complex, with significant multipath effects. This article addresses the reverberation problem caused by the multipath effect by increasing the protection time. The receiver is designed for low power consumption, with overall power consumption less than 65 mW. Experimental results show that the underwater acoustic remote control system has a long standby time and high reliability, with a bit error rate of less than 1%.