A new process of fabricating micro-pores oblate spherical powder (MOSP) with closed-pore structure was put forward, which is based on the traditional ball propellant process and the way of making the micro-capsule. 7% sodium sulfate solution is used as a dispersion medium for making MOSP instead of water. This method can effectively avoid the hole connection structure between pore walls in MOSP caused by water which is dissolved in nitrocellulose solution. Both changing the dosage of inner water phase and chemical foaming are used to prepare MOSP with closed-pore structure. The results indicate that: MOSP with uniform pore and closed-pore structure can be prepared when the amount of the inner water phase is less than 30 mL; MOSP with uniform pore, closed-pore structure and low bulk density can be prepared when 29% of solvent is evaporated.