Abstract: To study the effect of the bio-pesticide Wuyiencin on controlling tomato gray mould, toxicity experiments, pot tests and field trials were conducted. Toxicity experiments showed that Wuyiencin could strongly inhibit the mycelium growth of Botrytis cinerea, with an EC50 value of 10.0802μg/mL. Wuyiencin exhibited good protective effect and therapeutic effect against tomato gray mould in pot test, and the protective effect was prior to the therapeutic effect. At the same time Wuyiencin had a long persistence effect against Botrytis cinerea on tomato . In the field trials, the control effect of 100-fold dilution of 2% Wuyiencin AS was 83.93% 15 days after the third treatment. Besides, the effects of Wuyiencin on tomato fruit quality were studied. The results showed that content of soluble solids, vitamin C and soluble sugar were increased to some extent except titratable acid. In conclusion, 2% Wuyiencin exhibited excellent control efficacy against tomato gray mould and could improve tomato fruit quality, which could provide scientific basis for the reasonable application of bio-pesticide on tomato production.