The invention discloses omeprazole sodium for injection and a preparation method. Omeprazole sodium comprises the following preparation raw materials: omeprazole sodium, mannitol, a complexing agent,a pH (potential of hydrogen) regulator and water for injection, and further comprises tween 40. Liquid is prepared by dissolving the raw materials in the water for injection and freeze-dried. Parameters of a freeze-drying technology are as follows: pre-freezing at -45 DEG C for 2h, low-temperature sublimation at -45 to -5 DEG C for 3h and at -5 to 25 DEG C for 4h, a vacuum degree of 20-30Pa, resolution drying at 25 DEG C for 3h and a freeze-drying cycle of 12h. According to omeprazole sodium for injection, the freeze-drying time is significantly shortened from 25-50h in the prior art to 12h via prescription and preparation technology optimization; the energy can be saved; the failure probability of a freeze-drying procedure is significantly reduced; and the raw material loss caused by interruption of the freeze-drying cycle is avoided.