Abstract: In order to identity the pathogenic and classification status of jackfruit black rot, we took samples from the Baoting in area of Hainan Province. After field investigation, the strains were isolated and purified and the pathogenicity was identified. On the basis of morphological characteristics, the phylogenetic tree was established by combining the ITS sequence and EF1-α sequence of the pathogenic, the pathogen of the disease was finally identified. The results showed that the mycelia of the pathogenic LTHD006 grew rapidly, and were white and flocculent in the early stage, while the mycelia began to become black in the later stage, and the fungal colony be gan to become dense. In addition, it was clustered with Lasiodiplodia theobromae（ID: CBS175.26） into a branch with a support rate of 100%. Finally, the pathogen of black rot in jackfruit was identified as Lasiodiplodia theobromae. It was the first time that this disease has been reported in China, and the research results provided a theoretical basis for further study on the pathogenesis and prevention of black rot in jackfruit.