Underwater acoustic communication, compared with Wireless Sensor Networks (WSNs) used in terrestrial environment, poses unique challenges due to the harsh underwater environment, such as limited bandwidth capacity, high and variable propagation delays, high bit error rates, and temporary losses connectivity caused by multipath and fading phenomena in spite of using a variety of applications in many areas. In this paper we specify to develop the baseboard using characteristics of ARM9 processor based on low power consumption to enhance the performance, to improve a variety of restrictions. And we describe the process of the underwater communication that demonstrates and designs test-bed of the underwater acoustic sensor network with a similar actual environment.