The invention discloses a micro-balloon injection for a pharmaceutical composition of cefmenoxime hydrochloride / anhydrous sodium carbonate, which is characterized by comprising cefmenoxime hydrochloride, anhydrous sodium carbonate, polylactic acid- polyethylene glycol block copolymer, poloxamer 188, glycerol and mannitol. The optimal scheme of the invention is the micro-balloon injection for the pharmaceutical composition of cefmenoxime hydrochloride / anhydrous sodium carbonate, which is characterized by comprising 1 part of cefmenoxime hydrochloride, 0.12-0.18 part of anhydrous sodium carbonate, 1.2-4.5 parts of polylactic acid- polyethylene glycol block copolymer, 0.8-2 part(s) of poloxamer 188, 0.5-1 part of glycerol and 3-6 parts of mannitol. Compared with the prior art, the micro-balloon injection for the pharmaceutical composition of cefmenoxime hydrochloride / anhydrous sodium carbonate prepared by the invention has high stability, the preparation process is simple and is suitable for industrial production, and has high encapsulation efficiency. As anhydrous sodium carbonate is used as a latent solvent, the re-dissolution is good, and has an appropriate slow-release effect.