The invention discloses a recombinant low-virulent vaccine strain of chicken infectious bursal disease viruses (IBDV) and application thereof. In the invention, a major protective antigen gene VP2 of an epidemic superhigh virulent strain is cloned, the nucleotide of the gene VP2 is modified by mutation and then used for replacing a corresponding segment of a Gt genome of a low-virulent strain of the IBDV, so that the infectious clone of a recombinant genome of the IBDV is constructed, and the recombinant low-virulent vaccine strain is saved and identified by using an IBDV reverse genetic operation system. The microbial collection number of the vaccine strain is CGMCC No.3749. The recombinant low-virulent vaccine strain of the invention has high replicability, genetic stability and safety. The immune effect of the low-virulent vaccine strain of the invention is as good as that of the medium-virulent vaccine strain, but is superior to that of the low-virulent vaccine strain. The biological safety of the low-virulent vaccine strain of the invention is superior to that of the medium-virulent vaccine strain. As the vaccine strain, the recombinant low-virulent vaccine strain of the invention has the characteristics of high efficiency and low toxicity, is a good candidate vaccine strain and can be used for controlling chicken infectious bursal disease.