The invention provides a method for increasing the yield of organic tea by adopting a biocontrol strain. The method comprises the following steps: firstly, taking a bacterium solution of bacillus amyloliquefaciens which is cultured for 60 hours, wherein the initial bacterium concentration of the bacterium solution is 5 to 8*10<9>cfu/mL, and diluting the bacterium solution with sterile water by 2000 times; secondly, carrying out root watering treatment on an organic tea tree by adopting the bacterium solution obtained in the first step, wherein the use amount of the bacterium solution is 200 to 230mL per strain of the organic tea tree, and then watering for the second time after 15 days. The bacillus amyloliquefaciens is bacillus amyloliquefaciens Bam22 and has a preservation number of CGMCC (China General Microbiological Culture Collection Center) NO.11329. The organic tea tree is treated by adopting the biocontrol strains disclosed by the invention, so that the yield of the organic tea is improved obviously; the method has the characteristics of simple application method, low application amount of the biocontrol strain and good economic benefits.