Abstract: To clarify microorganisms resulted mildew on Hainan cigar tobacco leaves and screen their antagonistic strains to prevent tobacco leaves from mildew, mildew and antagonistic microorganisms were isolated from the surface of Hainan moldy cigar tobacco and purified. Morphological and molecular methods were combined to identify microbial species. The identification and screening results showed that the main microorganisms resulted mildew on Hainan cigar tobacco were Talaromyces funiculosus, Scopulariopsis brevicaulis and Aspergillus occultus. Two antagonistic strains with good antagonistic effects were screened out, namely Bacillus subtilis and Bacillus halotolerans. The main microorganisms resulted mildew on Hainan cigar tobacco were mainly Talaromycetes, Scopularia and Aspergillus strains. The screened two strains of Bacillus had good antagonism to mold, which provided a reference for the prevention and control of mildew on cigar tobacco.