To study the effects of iron migration on the stability of Huoxiang Zhengqi Soft Capsule.Methods:The distribution of iron in Huoxiang Zhengqi Soft Capsule was determined by UV and ICP-MS.The transport of iron was studied by adsorption thermodynamics model,quasi second-order kinetics model and Elovich model.Results:It was found that the migration of iron ions from the content to the shell was a spontaneous process driven by endothermic and entropy.The higher the temperature was,the faster the migration was; the migration behavior within the shelf life was basically in accordance with the quasi second-order dynamics model,and the migration behavior beyond the shelf life could be described by the Elovich model.Conclusion:The results of this study can be used to speculate the migration rule of iron in Huoxiangzhengqi Soft Capsule,and provide some basis for the formulation of product quality standards.