Based　on　the　engineering　geological　data　of　a　nuclear　power　plant　site,　five　engineering　geological　profiles　with　different　thickness　of　hard　cover　were　built,　and　five　one-dimensional　models　were　established　based　on　the　dynamic　and　static　parameters　of　rock　and　soil　layers,　and　the　effect　of　hard　cover　thickness　on　peak　ground　acceleration　and　acceleration　response　spectrum　of　analysis　models　was　analyzed　by　using　the　equivalent　linearization　method　of　one-dimensional　soil-layer　seismic　response.The　numerical　results　show　that　hard　cover　makes　peak　ground　acceleration　smaller　than　peak　acceleration　of　input　seismic　motion,　and　has　a　significant　seismic　isolation　effect.Hard　cover　thickness　has　significant　influence　on　peak　ground　acceleration　and　the　ratio　of　peak　ground　acceleration　to　input　peak　acceleration,　and　the　variation　characteristics　indicate　gradual　decrease　with　hard　cover　thickness　increase　as　a　whole.For　same　thickness　of　hard　cover,　the　ratio　of　peak　ground　acceleration　to　input　peak　acceleration　does　not　change　significantly　with　the　increase　of　input　peak　acceleration,　which　suggests　that　the　increase　of　input　peak　acceleration　does　not　cause　significant　differences　of　non-linear　effect　during　analysis　models.With　regard　to　same　input　peak　acceleration,　the　thicker　of　hard　cover,　the　wider　the　influence　frequency　band　of　ground　acceleration　response　spectrum.The　differences　of　the　acceleration　response　spectrum　during　models　above　the　period　of　6.0s　cannot　be　obviously　seen,　and　each　response　spectrum　is　nearly　the　same　with　the　increase　of　the　period,　while　the　response　spectra　below　the　period　of　6.0s　are　obviously　different.　©　2020,　The　Editorial　Board　of　Journal　of　Basic　Science　and　Engineering.　All　right　reserved.