N-acetylcysteine oral solution was prepared, and its quality control method was established.Using N-acetylcysteine as main drug and with measures of boiling solvents and filling nitrogen, the oral solution was prepared, HPLC method was used to determine the content of N-acetylcysteine, and methodol. confirmation and primary stability exploration were performed.The prepared oral solution is transparent and clear, sweet, fragrant and with stable quality.In the determination method, the linear relationship was good when the concentration was between 0.1-2.0 mg/mL, the regression equation was A = -50,714.33+ 7.21 × 106 ×C, r = 0.9995, the precision RSD = 0.922%, and the average recovery was 99.32%, with RSD = 0.826% (n = 5).The formula composition, preparation technol. and quality control method of the oral solution are scientific and rational, which could be used in its industrial production and quality control.