The　dynamic　behavior　of　concrete　has　obvious　strain-rate　dependency.　Here,　the　effects　of　loading　rate　and　its　sudden　change　on　concrete　compressive　failure　pattern　and　its　macroscopic　dynamic　properties　were　studied.　Considering　the　influence　of　concrete　heterogeneity,　from　view　point　of　meso-scale,　concrete　is　treated　as　a　three-phase　composite　composed　of　aggregate,　mortar　matrix　and　interfacial　transition　zone　(ITZ)　between　them.　The　damaged　plasticity　theory　combined　with　strain　rate　effect　was　used　to　describe　the　dynamic　properties　of　mortar　matrix　and　ITZ.　It　was　assumed　that　aggregate　phase　does　not　damage,　and　thus　aggregate　is　set　to　be　elastic.　A　planar　concrete　random　aggregate　structure　was　established　with　Monte　Carlo　method.　The　dynamic　compressive　tests　conducted　by　Dilger　et　al　were　simulated　at　first,　and　the　good　agreement　between　the　presented　numerical　results　and　the　experimental　data　indicated　the　feasibility　of　the　presented　meso-scopic　approach　and　the　reusonableness　of　the　selected　meso-scale　parameters.　Subsequently,　the　material　strain-rate　effect　was　discussed,　and　the　strain-rate　effects　of　a　concrete　meso-scale　heterogeneous　model　and　a　concrete　macro-scale　homogeneous　model　were　compared　and　studied.　Finally,　the　influence　of　the　sudden　change　of　loading　rate　during　the　softening　stage　on　concrete　failure　mode　and　macroscopic　mechanical　properties　of　concrete　was　analyzed.　Some　useful　conclusions　were　obtained.