A new manufacturing technique is proposed for transferring the waste double-base mortar propellant into oblate spherical propellant used in powder loads. The transferring process comprises grinding waste propellant, dispersing in water, swelling of grinded waste propellant powder in solvent, stirring for spheroidization, washing oblate propellant, screening and drying, obtaining the polished surface of the oblate propellant. The suitable process conditions are: ratio of solvent volume to propellant powder quality 1.0~2.0 ml·g^-1, ratio of water volume to propellant powder quality 6.0, consistence of dispersant in water 1.0 wt%~2.0 wt%, stirring speed 500~600 r·min^-1（linear velocity 4.0~5.0 m·s^-1）, swelling temperature and time 65~68 ℃ and 30 min respectively. Thus, the bulk density of the oblate spherical propellant increased from 0.70 g·cm^-3 to 0.95 g·cm^-3 (the crude propellant is), the flowing time of the propellant decreased from 7.5 s to 4.0 s. Experimental results show that the ballistic performance of the propellant meets the requests of American Standard PATMI.