In order to reuse ingredients from expired solid propellants, the extraction technology of ammonium perchlorate(AP) from composite solid propellant was studied by using water as solvent, and its effects were discussed. The propellants before and after extracting AP were comparatively observed by Scanning Electron Microscope. Results show that extraction time, extraction temperature and thickness of specimen greatly affect the AP extraction, while stirring speed has little effect. The optimum extraction conditions are: extraction time is 6 h, extraction temperature is 80 ℃, ratio of raw materials to solution is 1∶5, thickness of specimen is 2 mm and extraction frequency is 2 times, the AP extraction rate is 87%.