ASTM D1652-11 (2019) is a standard test method for the determination of cyclic oxygen content in epoxy resins. The standard covers both manual and automatic titration procedures and can quantitatively determine the epoxide content in epoxy resins from 0.1% to 26%. The epoxy content is an important variable in determining the reactivity of epoxy resins and the Coating performance made from them, so this method can be used to evaluate the mass and performance of epoxy resins. The test results are expressed in percentages and provide an important reference for the production, quality control and application of epoxy resins.