Abstract: Objective: The project aims to clarify the pathogen of the mango dew blotch disease, screen its antagonistic microorganisms in order to lay theoretical basis for the further prevention of the disease.Methods: Scanning electron microscope was used to observe the condition of the peel of diseased fruit. Conventional tissue separation method was applied to separate disease tissue. And the antagonistic microorganisms were screened by the flat-stand method. The pathogen and antagonistic microorganisms were identified in morphological and molecular biological methods.Results: It was found that mango dew blotch disease was caused by fungus.And the pathogen was identified as Cladosporium cladosporioides. Eight antagonistic strains against Cladosporium cladosporioides were isolated and screened from the soil in mango garden. The strain JS-8 and Y-1showed the highest and most stable antagonistic effect ( p < 0.05) . Results showed that the inhibition zone diameters were15.17 mm and 14.93 mm. Based on morphological, physiological and biochemical characteristics, and molecular biological methods, JS-8 and Y-1 were identified as Burkholderia gladioli, Debaryomyces hansenii.Conclusions: Mango dew blotch disease was mainly caused by Cladosporium cladosporioides.Burkholderia gladioli and Debaryomyces hansenii can be used for potential biocontrol strains of Mango dew blotch disease.