Abstract: To clarify the control effect of combined application of Bacillus amyloliquefaciens ZY-9-13 and Fusarium pseudograminearum carrying virus FC136-2A on tobacco black shank and to determine their optimal ratio, the colony growth rate method was employed to analyze the toxicities of the two and their compounds at different ratios against Phytophthora nicotianae. Field trials were conducted to compare the control efficacies of single agents and their optimal compound against tobacco black shank. The results showed that the biocompatibility between Bacillus amyloliquefaciens ZY-9-13 and Fusarium pseudograminearum FC136-2A carrying FpgMBV1 was satisfactory and their effective median inhibitory concentrations against Phytophthora nicotianae were 3.3×10⁵ CFUs per milliliter and 2.6×10⁵ spores per milliliter, respectively. The compounds of Bacillus amyloliquefaciens ZY-9-13 and Fusarium pseudograminearum FC136-2A carrying FpgMBV1 with volume ratio ranged from 6 ∶ 4 to 4 ∶ 6 demonstrating synergistic inhibitory effects. Among which, the compound volume ratio of 5 ∶ 5 yielded a field control efficacy of 73.49% which was significantly higher than those of single agents, with the highest inhibition rate and it's increase rate and the strongest synergistic effect.