Azido-PEG3-SS-NHS is a degradable linker containing 3 PEG units, with a molecular weight of 436.50 and a molecular formula of C₁₅H₂₄N₄O₇S₂. Its structure consists of three parts: an azide group, a cleavable disulfide bond (SS), and an N-hydroxysuccinimide ester (NHS). The production process requires precise control over the PEG chain polymerization degree and the introduction of functional groups through chemical modification to ensure a purity of ≥95%. This reagent is widely used in the synthesis of antibody-drug conjugates (ADCs). The NHS ester can efficiently couple with antibody amines, the disulfide bond undergoes responsive cleavage to release the drug in the tumor microenvironment, and the azide group supports subsequent bioorthogonal labeling. It is applicable for targeted therapy and the development of drug delivery systems.