Abstract: With the quick development of sonar technology, underwater acoustic communication plays an important role in marine scientific research and ocean development. Underwater acoustic communication transducer is the important part of the electric sound conversion system for acoustic communication. This paper studies a kind of underwater acoustic communication transducer using free-flooded ring typed tube. The ceramic components and shell structure of the transducer are optimized by the finite element simulation. A half-space directional underwater acoustic communication transducer is made and measured with the specifications as follows:11~23 kHz working band with 3 dB fluctuation, 133 dB maximum transmitting voltage response and the -3 dB vertical angle of greater than 180 degrees.