Specifies the terms and definitions, requirements, fabric defects, test and inspection methods, inspection rules, marking, packaging, transportation and storage of yarn-dyed easy-stretch elastic denim. The requirements for yarn-dyed easy-stretch elastic denim are divided into two aspects: intrinsic quality and appearance quality. The intrinsic quality includes density deviation rate, mass deviation rate per unit area, fiber content tolerance, constant force elongation, and constant force plastic deformation rate. , fixed elongation tensile stress, washing dimensional change rate, weft and skew dimensional change rate tolerance before and after washing, breaking strength, tearing strength, wear resistance, seam removal degree and dyeing fastness, appearance quality is width deviation, color difference , cloth surface defects.