The diseases of horticultural plants and their products will be getting more and severe,with the development of horticultural plant production and installation agriculture cultivation.The future direction of the disease control is to decrease chemical pesticides and to incerase greatly biocontrol without pollution and toxin.This paper outlined the mechanisms about controlling plant diseases by microorganisms,for example,inducing resistance,anti microorganism,mycorrhizal fungi,the suppressive soil against plant diseases.The research and application of biological pesticides were also introduced,including utilization of natural plant products,biopesticide and nematocide.The existing questions and future development were also discussed and reviewed.