Abstract: Resent research revealed that wind farms would impact on surveillance and navigation devices in civil aviation obviously. The assessment of these impacts is valuable for guiding site and type selection of civil aviation devices as well as site selection and project scheming of wind farms. The paper proposed a 3D visualized assessment method for wind farms' electromagnetic impacts. The assessment includes wind farm restricted areas assessment and wind turbine visibility assessment. The method utilized the parameters of surveillance and navigation devices and wind turbines to calculate the data of the boundary of wind farm restricted areas and the line of sight from a device to a wind turbine. The data obtained were employed to create a KML file, which could describe geographic information and its visualization. The KML file would be loaded in the 3D geographic information system platform such as Google Earth to fulfill the 3D assessment. The assessment results are visualized and explicit. The 3D assessment could be the bases for further detail assessment and relevant decision-making.