Aiming at the structure feature of certain type artillery cartridge case extractor, establish the dynamic simulation module of extractor after cartridge case extraction. Use backward difference method and related coordinate system motion equation to carry out dynamics analysis, discuss the change of ejection trace when the radio frequency and angle of fire are changed. Acquire the cartridge trace when the angle of fire is fixed and radio frequency is changed. And acquire the cartridge trace when the angle of fire is changed and radio frequency is fixed. The results show that, at the same angle of fire, the speed of cartridge case into ejection guidance barrel is accelerated when radio frequency is improved. At the same firing frequency, when the angle of fire is added, the more power of grab arm in gravity direction, the shorter time of cartridge on ejection barrel.