The invention relates to a strain of streptomyces albus for preventing and controlling aspergillus flavus and aflatoxin and application thereof. Microbes are separated from intestinal tracts of sea cucumbers under an oligotrophic culture condition by using a culture medium only containing agar powder; and in addition, the strain of streptomyces albus is separated from the intestinal tracts of healthy sea cucumbers. After being fermented, the streptomyces albus generates a great number of active secondary metabolites capable of inhibiting the growth of a pathogenic fungus of the aspergillus flavus and the synthesis of the aflatoxin. In addition, the streptomyces albus can completely inhibit the pollution of fungi and fungal toxin in the storage process of grains such as peanuts; and wide application prospects are realized in the field of grain safety.