To identify the microbial species responsible for the spoilage of slurry processed reconstituted tobacco and to characterize their biological properties, two mold strains were isolated from the contaminated samples. Morphological and molecular biological methods were used to identify and analyze the species and the biological characteristics of these isolates. The results showed that the spoilage was caused by mold belonging to Aspergillus, and two strains were obtained and identified as Aspergillus niger(A. niger) and Aspergillus flavus(A. flavus). The growth rate of A. niger was higher than that of A. flavus on all culture media tested, including Bengal red media, PDA media, CYA media, and tobacco extract-based media at concentrations of 1%, 5%, 10% and 20%. The optimal growth temperature for both strains ranged from 30-35 °C, and growth was effectively inhibited at 4 °C and at temperatures≥45 °C. Both strains were capable of growing over a wide pH range(3-10), with the maximum biomass accumulation observed at pH 6. Ultraviolet(UV) irradiation significantly inhibited fungal growth on the slurry processed reconstituted tobacco, and A. flavus was found to be more sensitive to UV treatment than A. niger. These findings indicate that temperature modulation and UV treatment are effective measures for controlling microbial growth on slurry processed reconstituted tobacco.