The invention aims at providing an I-colony fowl adenovirus 4 strain, which is preserved with preservation number of CCTCC No. V201541. The I-colony fowl adenovirus 4 YBAV-4 strain disclosed by the invention is excellent in specificity and immunogenicity; a specific precipitation line does not appear in specific positive serum chicken SPF chicken serum such as infected cell sap and egg drop syndrome resisting virus, chicken infectious bursal disease virus, Newcastle disease virus, chicken infectious laryngotracheitis virus, chicken Marek's disease virus, avian influenza and the like, while an obvious specific precipitation line appears in I-colony fowl adenovirus 4 specific serum. The strain disclosed by the invention, as a vaccine strain which is good in manufacturing effect, is capable of preventing chicken hydropericardium syndrome, and the strain is applicable to identification of virus serotype and investigation on epidemiology.