In　order　to　obtain　more　accurate　spectral　accelerations　for　seismic　design,　2661　strong-motion　acceleration　records　in　the　Next　Generation　Attenuation　(NGA)　West2　database　were　statistically　analyzed,　the　effects　of　earthquake　parameters　on　the　middle　to　long　periods　of　the　ground　motion　spectral　accelerations　were　studied,　and　normalized　horizontal　spectral　accelerations　on　bedrock　(site　classification　I　in　the　Chinese　standard)　and　non-bedrock　(site　classification　II　and　III　in　the　Chinese　standard)　for　seismic　design　were　established.　The　results　indicated　that　the　spectral　accelerations　of　the　ground　motion　were　significantly　influenced　by　site　conditions　and　earthquake　moment　magnitudes,　meanwhile　they　were　slightly　influenced　by　distance　parameters　of　the　earthquake　source.　Comparing　to　the　spectral　accelerations　for　seismic　design　suggested　in　RG1.60　of　USNRC　and　GB50267-97　in　China,　the　spectral　accelerations　of　the　ground　motion　obtained　in　this　paper　could　evaluate　the　effects　of　site　surface　geology　characteristics　and　earthquake　moment　magnitudes　on　the　middle　to　long　periods　of　the　ground　motion　more　reliably.　Finally,　the　spectral　accelerations　for　seismic　design　considering　the　influences　of　site　conditions　and　seismotectonic　environments　were　established,　which　could　be　used　as　the　ground　motion　inputs　in　the　site　selection　and　seismic　design　of　nuclear　power　plants　on　non-bedrock　sites.　©　2020,　Editorial　Board　of　Journal　of　Nuclear　Power　Engineering.　All　right　reserved.