The invention belongs to the plant quarantine standard sample technology research and development field, and in particular, relates to a preparation method for a soybean standard sample. The preparation method for the wild soybean standard sample mainly includes determination of an expert group, standard sample source, standard sample expanding propagation, standard sample screening, standard sample production process, standard sample uniformity inspection, standard sample stability inspection and standard sample storage; wild soybean seeds collected in fields are used as raw material, wild soybean standard samples having representativeness are prepared through isolation planting, expanding propagation, screening, preparation, uniformity inspection, stability inspection, packaging and storage and other procedures, an identification basis is provided for plant inspection and quarantine works, and a real object reference is provided for protection of national species resources.