The invention discloses a chicken infectious bursal disease virus VP2 gene, an expression product and a subunit vaccine thereof, and an application of the vaccine. The invention further provides a nucleic acid sequence of the chicken infectious bursal disease virus VP2 gene, a primer for cloning the nucleic acid sequence, an expression vector containing the nucleic acid sequence, an engineering bacterium obtained through conversion of the expression vector, a chicken infectious bursal disease virus VP2 protein encoded by the nucleic acid sequence, expressed by the expression vector or separated from the engineering bacterium, and a chicken infectious bursal disease virus-like particle formed through self-assembling the chicken infectious bursal disease virus VP2 protein. The invention further provides the subunit vaccine prepared from the chicken infectious bursal disease virus VP2 protein. The subunit vaccine is prepared from the chicken infectious bursal disease virus-like particle.The subunit vaccine is applied to prevent chicken related diseases caused by the chicken infectious bursal disease virus. The subunit vaccine has the advantages of low production cost, simplicity in operation, good biological security, and effectiveness in prevention of infection of the chicken infectious bursal disease virus to chickens.