Abstract: Provided is a method for measuring the bismuth content in a colloidal bismuth pectin or a colloidal bismuth pectin-contained preparation. A protonic acid is used to dissociate bismuth from a colloidal bismuth pectin, the principle of the characteristic reaction between bismuth and potassium iodide to produce yellow potassium bismuth iodide is used; ultraviolet-visible spectrophotometry is for measurement; an external standard method is for calculation. The method has strong specificity, a good linear relationship, high accuracy, good repeatability and high sensitivity. The method is able to act as a quality control method for bismuth in a colloidal bismuth pectin or a colloidal bismuth pectin-contained preparation to effectively control the product quality.