Ultraviolet light communication is a new means of optical information transmission technology developed since 1990's. In this paper, some key technologies developed from the experiment are described in detail. These technologies include the designs of high speed UV source frequency modulator, high sensitive optical receiver system and the design of weak signal detect and process modular, etc. The UV communication system has accomplished good voice and high speed digital data bidirectional communication in semi-duplex way and its maximal communication baud rate is up to 9600 bps which is twice as the baud rate of the UV communication system made by GTE company for USA navy in 2000. Furthermore, in some distance, the system can achieves a non-line-sight communication.