A　time-domain　boundary　element　method　was　applied　to　simulate　the　fast　crack　propagating　process　under　dynamic　loading.　The　crack-growth　direction　was　determined　by　the　maximum　circumferential　stress　criterion.　The　instantaneous　crack-tip　velocity　was　approached　by　a　bisection　technique.　New　elements　of　inconstant　length　were　added　to　the　moving　crack-tip　to　simulate　the　crack　propagation.　The　simulation　was　analyzed　and　compared　to　the　corresponding　experimental　and　numerical　results.