In　the　rock　engineering,　it　is　very　significant　to　focus　on　the　failure　mechanical　behavior　of　rocks　containing　all　kinds　of　flaws.　In　this　research,　the　strength,　deformation　and　crack　evolution　behavior　of　sandstone　containing　a　single　oval　flaw　under　uniaxial　compression　were　evaluated　by　experiment　and　numerical　simulation　using　a　two-dimension　particle　flow　code　(PFC2D).　The　experimental　results　show　that　the　peak　strength　and　elastic　modulus　first　decrease　and　subsequently　increase　with　increasing　oval　flaw　angle　(a);　the　lowest　value　appears　when　alpha　=　15　degrees,　but　the　oval　flaw　angle　has　little　effect　on　peak　strain.　The　oval　flaw　angle　has　a　great　effect　on　crack　initiation　and　propagation,　as　observed　from　photographic　monitoring　and　the　AE　technique.　The　AE　counts　of　flawed　specimens　show　several　larger　peak　values　prior　to　peak　strength,　which　correspond　to　crack　initiation　and　propagation　in　the　specimen.　And　then,　PFC2D　was　used　to　simulate　sandstone　containing　a　single　oval　flaw　under　uniaxial　compression,　and　the　simulated　results　are　in　good　agreement　with　the　experimental　results.　By　analyzing　the　stress　surrounding　the　oval　flaw　periphery,　we　explain　that　the　wing　tensile　crack　initiation　area　transfers　from　the　middle　of　the　oval　flaw　periphery　to　the　tip　of　the　oval　with　increasing　oval　flaw　angle,　shear　crack　is　easily　initiated　at　the　tip　of　the　oval　flaw,　and　the　stress　of　the　first　wing　crack　increases　with　increasing　oval　flaw　angle.　Finally,　the　variance　of　the　stress　of　the　measurement　circle　along　the　crack　propagation　path　with　axial　strain　was　analyzed　and　combined　with　the　crack　evolution　process　and　stress-strain　curve.　As　a　result,　the　crack　evolution　mechanism　and　cracking　type　in　sandstone　containing　a　single　oval　flaw　under　uniaxial　compression　are　revealed.