In recent years, the development of small hydro power stations has been widely applied accros Vietnam. This paper shows the complete design process for a hydro turbine controller. The algorithm is given based on the typical mathematical models of the target system. The controller parameters are obtained from the novel analytical formulars, which take into account the wide range of operating points of hydraulic turbine. In addition, the paper also presents the details design of microcontroller based implementation, the use of hardware in loop (HIL) to verify the model in the laboratory condition. The experience result from hydro controller of Rhyninh hydro turbine unit in Central Vietnam is given as an illustration.