The invention relates to a chemical method for synthesizing a benzsulfamide HDAC (Histone Deacetylase) inhibitor by taking paratoluensulfonyl chloride and ortho-nitroaniline as materials. The method comprises the following steps: (1), synthesis of a toluene sulfonamide compound, wherein the paratoluensulfonyl chloride and ortho-nitroaniline are condensed at a high temperature by taking pyridine as a solvent to obtain the toluene sulfonamide compound; (2), synthesis of a primary amine compound, wherein bromination is carried out on methyl of a benzene ring by NBS (N-Bromosuccinimide) under action of AIBN (2,2-Azobisisobutyronitrile), sodium azide is used to convert the methyl into an azide, and then dehydrated into the primary amine compound under action of triphenylphosphine; (3), synthesis of an amino compound, wherein 3-hydroxymethylpyridine and the primary amine compound are condensed to obtain nitryl compound containing sulfamide under action of CDI (Carbonyldiimidazole), and stannous chloride is used to reduce the nitryl compound to obtain the amino compound. An activity test indicates the compounds have tumor cell proliferation resistance equivalent to that of a positive drug MS-275, and have potential of being developed into anti-tumor drugs.