A　two　dimensional　axisymmetric　finite　element　analysis　is　preformed　using　AUTODYN-2D　hydrocode,　to　simulate　the　dynamic　response　of　explosive,　named　PBX9404　which　is　located　behind　double-shell,　by　the　impact　to　shell　surface　resulted　from　high　velocity　spherical　projectile.　Simulation　results　shows　that　shock　to　detonation　transition　occurs　when　impact　velocity　is　between　3.6~3.9km/s;　but　when　the　velocity　increases　to　4~4.3km/s,　projectile　will　break　up　into　pieces　and　the　surface　momentum　density　of　debris　cloud　to　second　shell　will　decrease　dramatically　so　no　shock　to　detonation　could　occur.　When　the　velocity　further　elevates　to　4.4　km/s　and　above,　projectile　kinetic　energy　will　cover　the　energy　of　projectile　break-up,　and　also　provide　sufficient　energy　to　further　increase　the　surface　momentum　density　of　debris　cloud,　with　a　result　that　shock　to　detonation　can　be　observed　again.　In　conclusion,　there　is　a　velocity　blind　zone　in　shock　to　detonation　of　high　velocity　projectile　to　double-shell　charges.　©　(2012)　Trans　Tech　Publications,　Switzerland.