The invention relates to an artificial infection method of a tree coral. The technical scheme is described as follows: firstly, randomly dividing strains obtained and separated from a diseased coral into a plurality of test groups; simultaneously carrying out artificial infection on healthy corals by utilizing the parallel groups of mixed bacterium liquid; respectively carrying out artificial infection on the healthy corals by utilizing the strains of the test groups capable of inducing the healthy corals to be diseased; and finally, confirming the bacterium pathogens capable of inducing the healthy corals to be diseased, therefore, processes of rapidly and accurately separating and identifying the coral bacterium pathogens are realized. The method disclosed by the invention has the beneficial effects that: aiming at coral bacterium diseases, the rapid separation and confirmation of pathogenic bacteria are realized; and compared with a traditional method, the method is capable of greatly reducing the working intensity of coral bacterial disease epidemiological investigation.