In order to boost the reliability of a floating TUV system, the research represents the central control system to be a Depth-setting TUV control system based RS-485 network. The paper will show the three aspect technology of this RS-485 network. According to the characteristics of the RS-485 network, the control architecture, the hardware structure and the communication protocol of this distribution system will be illustrated in the passage. Then, the passage will published the material object of the floating TUV. Given the experiment method and conclusion, it proves the distributed system is more stability, reliable, fast in response than ever in the last part.