Abstract: In order to fit the construction of hydrologic information center or the early warning and forecasting system, an acoustic Doppler current profiler is developed, it can truly reflect the flow field, and get a current profilers through once measurement. In this paper firstly the system function of Doppler current profiler is described; and then secondly, combining the characteristic of Modbus protocol, an example of sending and receiving data is presented. Based on the OMAPL137 hardware and the embedded Linux operating system, a scheme of implementing of Modbus RTU protocol is realized. The scheme is verified by communication experiments. The experimental results show that this method can effectively carry out data transmission for acoustic Doppler current Profiler in data transmission of hydraulic system.