The　physical　meaning　of　site　classification　is　not　clear　in　the　current　seismic　design　code　for　buildings,　at　the　same　time,　the　boundary　of　site　classification　is　easy　to　cause　the　divergence　of　design　ground　motion　parameters.　For　the　above　problems　and　deficiencies,　some　suggestions　are　given.　To　solve　the　problem　that　the　physical　meaning　of　site　classification　is　not　clear,　on　the　basis　of　the　current　site　classification　method,　according　to　the　site　classification　index　such　as　the　covering　layer　thickness　and　the　equivalent　shear　wave　velocity,　the　sites　are　classified　by　two-level:　the　first　level　classification　is　consistent　with　the　current　one,　which　classifies　sites　based　on　the　fundamental　period　of　the　site　and　the　thickness　of　the　overburden　layer;　the　second　level　classification　further　considers　the　degree　of　hardness　of　the　geotechnical　medium　based　on　the　first　level　classification,　and　sub-classification　according　to　equivalent　shear　wave　velocity.　Based　on　the　current　research　on　seismic　disaster　and　seismic　motion　characteristics　of　thick　soft　site,　combined　with　the　development　of　long-period　constructions,　the　site　classification　is　expanded　from　the　original　four　categories　to　five　categories,　at　the　same　time,　the　boundary　of　each　classification,　especially　the　boundary　of　class　II,　III　and　IV　sites,　is　limited　from　the　original　open　type,　which　can　effectively　avoid　the　problem　of　divergence　of　design　ground　motion　parameters　caused　by　site　classification.　The　related　research　results　can　provide　reference　for　site　classification　and　determination　of　design　ground　motion　parameters.　Copyright　©2021　ACTA　SEISMOLOGICA　SINICA.　All　rights　reserved.