A method for the content determination of omeprazole Na was presented. RP-HPLC was used. Amethyst C8 column was used with mobile phase consisted of 0.01 mol/L Na2HPO4 solution (pH adjusted to 7.6 with H3PO4)-acetonitrile (75:30, V/V) at the flow rate of 1.0 mL/min. The detection wavelength was 302 nm, and column temperature was 30°C. The sample size was 20 μL. The linear range of omeprazole Na was 8.7-43.4 μg/mL (r=0.999 9)with an average recovery of 100.65% (RSD=0.60%, n=9). RSDs of precision, stability, and reproducibility tests were all lower than 0.38%. The method is simple, rapid, accurate, and specific, and it is suitable for the content determination of omeprazole sodium.