Abstract: Citrus huanglongbing (HLB) is caused by Liberibacter whichincludes three species.HLB can be transmitted by seedling and grafting as well as psyllid.There are some diagnoses methods of HLB disease,including the symptom diagnosis of the diseased leaves in field,serum detecting method and the pathogen diagnosis using electron microscopy as well as molecular detecting method,such as PCR.Hitherto,there are no effective methods to protect citrus plant from HLB.The integrated pest management (IPM) is available in protecting the plant from the disease now,such as eliminating the pathogen source and cutting transmitting approach of the HLB,etc.It is very important for both the realization of the pathogen characterization and the management of the disease to study the artificial pathogen culture,disease-resistant plant breeding and disease-inducing mechanism as well as controlling method for the disease.