The invention relates to an antibody against fucosylated protein GP73, a method for preparing the antibody against the fucosylated protein GP73, a reagent for diagnosing liver cancers, a kit for diagnosing the liver cancers, application of the reagent and / or the kit to preparing products for diagnosing liver diseases and a method for preparing purified fucosylated protein GP73. Occurrence, development and metastasis of liver cancers are diagnosed by detecting the fucosylated protein GP73 or the antibody. The antibody against the fucosylated protein GP73 can be more widely used for affinity chromatography, cDNA library screening, immunologic diagnosis or pharmaceutical preparation.