A　systematic　understanding　of　the　physical　and　mechanical　behavior　of　high-temperature　rocks　after　different　cooling　methods　can　provide　a　theoretical　basis　for　underground　coal　gasification　and　geothermal　resource　exploitation.　In　this　study,　a　series　of　tests　were　carried　out,　including　wave　velocity　and　split　Hopkinson　pressure　bar　(SHPB)　test,　to　analyze　the　dynamic　mechanical　properties　of　thermal-treated　sandstone　with　different　heating　temperatures　(25　degrees　C,　200　degrees　C,　400　degrees　C,　600　degrees　C,　800　degrees　C)　under　nature,　water,　and　liquid　nitrogen　cooling　treatment.　The　dynamic　stress-strain　curves　of　rock　were　obtained,　and　the　relationships　between　three　parameters　(dynamic　strength,　elastic　modulus,　and　peak　strain)　and　temperature　were　investigated.　The　fragments　after　impact　compression　were　collected　for　the　screening　test,　and　the　degree　of　fragmentation　of　sandstone　after　different　heating　temperatures　and　cooling　treatments　was　discussed.　The　results　demonstrate　that　under　the　three　cooling　treatments,　the　wave　velocity,　elastic　modulus,　and　dynamic　peak　strength　of　sandstone　decrease　with　the　increase　in　thermal　treatment　temperature　while　the　peak　strain　and　fracture　degree　increase　as　the　temperature　rises.　When　the　temperature　is　higher　than　400　degrees　C,　the　physical　and　mechanical　properties　of　sandstone　significantly　deteriorate.　Compared　with　natural　cooling,　the　rapid　cooling　of　water　and　liquid　nitrogen　more　severely　damages　the　thermal　treatment　sandstone.　Moreover,　the　invasion　of　water　weakens　the　connection　between　mineral　particles,　leading　to　the　most　significant　deterioration　of　the　mechanical　properties.