Abstract: The vertical water level observation platform is often used to record water level data in long-term important hydrological stations. The hydrological characteristics of tidal river reach are complex, and the water level is affected by hydrodynamic factors such as river flow, tide and waves, etc., which can easily cause problems of platform structure stability and water level observation accuracy. Therefore, for the Minjiang estuary hydrological station project we study and design a vertical water level observation platform in the tidal river reach. Through the relevant codes and standards analysis, space numerical model calculation and project cost comparison, we put forward a principle for the scheme selection of water level observation platform and aperture determination. It is suggested that the conventional water level observation platform in the tidal river reach should adopt the shore-type scheme, while the island-type elevated pile caps platform scheme should be adopted for special needs; the diameter of the inlet hole should be determined by standard formula calculation while reserving an appropriate margin. The practice showed that the observation data of the new water level observation platform of Minjiang estuary station met the accuracy requirements of water level observation in tidal river reach. The research results can be used as reference for subsequent similar projects.