ANSYS　was　used　to　focus　on　comparative　analysis　of　several　artificial　boundary　conditions　that　are　widely　used　in　engineering　applications.　The　accuracy　and　stability　of　dynamic　analysis　results　were　then　analyzed　in　details　of　a　semi-infinite　foundation　with　different　artificial　boundaries　and　different　frequency　input　loads.　Lastly,　the　seismic　response　of　a　gravity　dam-foundation　rock　system　was　explored　numerically.　Experimental　results　revealed　the　simulation　accuracy　of　artificial　boundaries　was　closely　related　to　the　dynamic　characteristics　of　input　load　and　the　elastic　wave　velocity.　When　the　input　load　frequency　was　high,　only　the　material　with　comparably　higher　elastic　wave　velocity　could　maintain　the　stability　of　the　artificial　boundary.　Viscoelastic　artificial　boundary　is　practically　simple　and　can　better　simulate　the　semi-infinite　material　elastic　recovery　ability　and　energy　radiation　outside　the　boundary.