Abstract: A wind tunnel drop-model testing technique is applied to study the dynamic separational process for the internal weapon from the open weapon cabin ejection for the separation safety problem of supersonic internal weapon ejection delivery, The light model similar design method is used in the wind tunnel drop-model testing which all movement is strictly comparable in addition to lack of vertical acceleration and the lack of the vertical acceleration can cause displacement deviation real displacement. in the end we use a simple formula method to compensation the lacking vertical displacement. the experiment gives the law of separation trajectory and attitude for the different initial ejection separation condition, the test Mach number is Ma= 1.5. The results show that the initial separation angle velocity has a great influence on the motion trajectory and the attitude angle for the internal weapon. When the initial separation angle speed is \omega _z0^s = 0^\circ/\rm s, the internal missile firstly moves down to the disturbed flow field far from the cariier the separation,then it gradually moves towards to the carrier direction and collides the carried vehicle. The experimental results of high speed wind tunnel are unsafe,but the result is optimistic after the formula is corrected. This shows that the unsafe separation of missiles obtained by the high speed wind tunnel test may not necessarily occur for the aircraft and the results that obtained by the high speed wind tunnel test are conservative. When the initial separation angle speed is \omega _z0^s = 15^\circ/\rm s, \omega _z0^s = 30^\circ/\rm s, the movement trend of the embedded missile is almost the same and there is no approaching the carrier aircraft. The embedded missile which has a certain initial delivery angle is conducive to the safe separation of internal weapons.