This document specifies the requirements, test methods, inspection rules, marking and accompanying documents, packaging, transportation and storage of ammonium sulfate by-product of D-p-methylsulfonylphenylserine ethyl ester (D-ethyl ester). This document is applicable to the ammonium sulfate aqueous solution produced in the esterification process of D-p-methylsulfonyl phenylserine ethyl ester, and the ammonium sulfate by-product of D-p-hydroxyphenylglycine methyl ester obtained through extraction, decolorization, concentration and centrifugation, etc., mainly Used for municipal greening, rare earth mining, leather deliming agent, etc.