A kind of polyethyleneglycol modified dose and its preparation method and application containing Lin Ben diquines functional group.The dressing agent is divided into single-ended polyethyleneglycol modified dose of closing, both ends with polyethyleneglycol modified dose of different functional group of polyethyleneglycol modified dose of functional group and both ends, its application concentrates on modifying the drug with pharmacological activity containing sulfydryl, achieve the purpose that extend half-life period, reduce immunogenicity, or is coupled the purpose of pharmacological active agent as the both ends linker.Polyethyleneglycol modified dose containing adjacent benzene diquinone active function groups has the advantages that pointed decoration sulfydryl, dressing agent hydrolysis resistance be strong, modified outcome is stablized.