In order to receive signals emitted underwater nodes by deepwater riser monitoring system, we design a lownoise and lowpower underwater receiver. In the environment of marine, the transmission power of the transmitter due to propagation loss and propagation of noise interference, resulting in distortion of the received signal, attenuation, and dynamic range increases other issues. These are not conducive to the backend digital processing. The system selects the lownoise chips to reduce system noise by sixthorder elliptic filter, select the desired frequency band signal by using AGC achieve a large dynamic range compression. The results of experiments in the sea show that the system is a high sensitivity, low noise, low power consumption and big receiver dynamic range system.