Abstract: Energy estimation of a tidal power station is a core subject in its planning and design stage. This paper presents an estimation of the theoretical tidal energy output from a tidal power station by the water balance principle and a method for calculation of long-series hydro energy regulation of the station in different operating conditions under its specific modes of development and exploration. A user-friendly software was developed to calculate annual energy output and applied at the planning and design stage of the Wenzhou Ou’fei tidal power station. The results of application to this engineering case show that the software has a satisfactory accuracy and application value.