Loess-high filling sites formed by cutting off hilltops exert a large influence on the characteristics of the ground motion parameters. Based on an actual project, calculation sections with different filling heights were constructed, and the one-dimensional equivalent linearization method was used to calculate the ground motion parameters of soil layers to analyze the influences of bedrock ground motions and height of the filling soil on the ground surface amplification effect. The seismic amplification coefficient of the site decreased with increasing filled height. In addition, the seismic amplification coefficient of the site decreased faster under the action of frequent and basic earthquakes than under the action of rare and extremely rare earthquakes. When the filled height reaches a certain level, the amplification effect stabilizes; variations in filled height change the shape of the surface acceleration response spectrum. At a certain filled height, the bedrock type shows no obvious influence on the surface ground motion characteristics. This research provides a reference for seismic safety evaluation and structural seismic design of loess-high filling sites.