Abstract: Aspergillus flavus and its aflatoxin seriously threated the quality and safety of agricultural products. This study was aimed to explore the effect of Leclercia adecarboxylata wt16 on Aspergillus flavus growth and producing aflatoxin. A strain of Leclercia adecarboxylata wt16 strain was screened from the Hubei Huangpi. The effect of wt16 on the growth of Aspergillus flavus and the aflatoxin production was studied through their coculture in the medium. The results showed that wt16 could significantly inhibit the growth of Aspergillus flavus and aflatoxin production in medium,the rate of wt16 for its growth inhibition was 77%~92%,the rate of wt16 for its aflatoxin production was 90%~96%. And wt16 could change the morphology of Aspergillus flavus by Scanning Electron Microscopy(SEM),it could change the mycelium of Aspergillus flavus into irregular shape,the slender mycelium could be breaked into small sectional shape,and its surface could become more smooth. It also played a same role in growth and aflatoxin production of Aspergillus flavus on peanuts. After the further studied,it was found that fermentation supernatant had the effective ingredient to inhibit aflatoxin synthesis. The results showed that the best incubation time of wt16 was more than 4 d,and the culture temperature was 15~40 ℃.