Abstract: To evaluate the types of molds and main molds on cigar tobacco leaves from different production areas in Hainan Province at the stem-drying stage during air-curing, plate counting method was used to compare the amounts of molds on moldy tobacco leaves from five planting areas (Danzhou, Ledong, Tunchang, Dongfang and Wuzhishan). The molds were identified through morphology and ITS sequencing, and the effect of temperature on their growth was investigated. By artificially inoculating the molds on tobacco leaves without mold, the main mildew-causing fungi were determined according to the colonization of the strains, and the effects of the molds on the volatile components in the leaves were analyzed by headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that: 1) There were differences in the mold species on the moldy leaves from these areas. Aspergillus chevalieri was detected in the moldy samples from Tunchang, Dongfang and Wuzhishan, accounting for 99%, 90% and 90% of the total mold amount, respectively. Penicillium citrinum was found in the moldy samples from Danzhou and Ledong, accounting for 60% and 45% of the total mold amount, respectively. Penicillium oxalicum only existed in the Danzhou sample, accounting for 20%; Aspergillus occultus appeared in the Ledong sample, accounting for 50%. 2) The growth of the four main mold strains was inhibited at 37 ℃. 3) The Aspergillus occultus strain had a strong ability to cause mildew and tended to cause mold on Hainan cigar tobacco leaves. 4) The contents (mass fractions) of esters in Hainan cigar tobacco leaves increased significantly after molding, and methyl hexadecanoate, methyl pentadecanate, methyl stearate and methyl 9, 12-octadecadienoate could be used as markers of cigar tobacco leaf mold.