Abstract: The statistical characteristic parameters of marine evaporation duct height over the world ocean areas are important for marine electromagnetic system design studies and operational planning. In order to give more accurate depiction of evaporation duct height over the world ocean，the database of evaporation duct heights in the world seas with spatial resolution of about 1°×1°is found used the (National Centers for Environmental Prediction NCEP) reanalysis data, for 2000 to 2011, and an improved evaporation duct model, which was found originally by America naval postgraduate school, and improved using version 3.0 of the coupled ocean atmosphere response experiment (COARE) bulk algorithm. With the database, the spatiotemporal features of evaporation duct heights in China for different seas and months are studied，also its generation mechanism is discussed. The results are important for radar, communication, navigational fixing system design and operational planning.