Objective By assessing the uncertainty of the determination results for the concentration of ambroxol hydrochloride injection,the reliability of the concentration measurement results is improved,ensuring the safety and efficacy of high-risk dosage form medications.Methods The uncertainty assessment of the content determination results by HPLC external standard method was conducted using both the TOP-DOWN method and the GUM method in the past.The TOP-DOWN method evaluated after synthesizing two components:the combined bias uncertainty component and the intermediate precision uncertainty component.The GUM method analyzed six sources of uncertainty based on the experimental process and evaluated after synthesizing the uncertainty.Results When the confidence level was 95％,the expanded uncertainty assessed by the TOP-DOWN method and the GUM method was 1.84％and 2.36％respectively(K=2).Conclusion The results from both assessments indicated that the determination of ambroxol hydrochloride injection content was reliable,ensuring the safety and efficacy of the drug.