Abstract: Arginine ibuprofen tablets were taken, removed the coating, and ground. The power was dissolved in a mixture of acetonitrile and water at the volume ratio of 8∶2. The main drug ibuprofen and the key excipient arginine in arginine ibuprofen tablets were determined by high performance liquid chromatography (HPLC), using Dikma Silversil C₁₈ bonded silica gel column (250 mm×4.6 mm, 5.0 μm) as the stationary phase, and the mixed solution composed of acetonitrile and water (water adjusted to pH 2.5 with phosphoric acid) at the volume ratio of 8∶2 as the mobile phase. The photodiode array detector was used to detect ibuprofen at 230 nm and arginine at 208 nm, and the standard curve method was used for quantitative analysis. As shown by the results, ibuprofen could be completely separated from arginine under the optimized chromatographic conditions. Linear relationships between the corresponding peak areas and mass concentrations of ibuprofen and arginine were found in definite ranges, with detection limits (3S/N) of 0.45 mg·L⁻¹ and 18 mg·L⁻¹, respectively. RSDs (n=6) of the determined values in the precision test were less than 3.0%. It was shown by the stability test results that the mixed reference solution and sample solution were stable within 24 h at room temperature. And the recoveries were in the ranges of 99.1%-102% for ibuprofen and 97.4%-102% for arginine, respectively.