Abstract: OBJECTIVE To study the effect of iron ions and oxygen on stability of terbutaline sulfate nebulized solution, and to explore the control limits of iron ions and headspace oxygen. METHODS The content of related substances and the color of the medicine liquid were taken as the inspection indicators, the relationship between the content of iron ions and oxygen and the stability of the samples was clarified by ICP-MS and HPLC detection methods. RESULTS The higher the concentration of iron ions and oxygen, the worse the stability of the sample, which need to be strictly controlled. CONCLUSION The prepared samples have good stability by controlling the iron ion concentration in the liquid medicine to be less than 45 ng·mL^-1and the residual oxygen in the headspace to be less than 2.0%. This limit can be controlled as a critical process parameter of the production process.