Galactomannan antigen and preparation method thereof

The invention relates to a preparation method of a galactomannan antigen. The method comprises the steps that breaking, centrifugation, alcohol precipitation, washing and drying are carried out on a living body rich in galactomannan, and galactomannan crude extract is obtained through separation; hydrazinolysis and hydrolysis are carried out on the obtained galactomannan crude extract in sequence; an enzyme is added to a hydrolysis product for enzymolysis, and the enzyme and small molecular substances in an enzymolysis product are removed; a product is purified through an ion exchange column, an affinity column and gel chromatography, and the pure galactomannan antigen is obtained; the obtained pure galactomannan antigen is identified. The galactomannan antigen obtained through the preparation method is high in purity, the inference of galactosamine, protein, miscellaneous sugar possibly included in the galactomannan crude extract is eliminated, and the preparation method can be used for preparing aspergillus fumigatus antibodies.