The invention provides a triple vaccine. Antigens of the triple inactivated vaccine include an inactivated chicken newcastle disease La Sota virus strain, an inactivated H9 subtype avian influenza QF01 strain and an inactivated I-group 8b type fowl adenovirus Hexon protein. The invention further provides a preparation method of the triple inactivated vaccine. The preparation method comprises the following steps of enabling the I-group 8b type fowl adenovirus Hexon protein to be inactivated through pyrrole, and performing mixing and emulsifying on the inactivated I-group 8b type fowl adenovirusHexon protein, an inactivated newcastle disease virus concentrated solution and an inactivated avian influenza virus concentrated solution to obtain the triple inactivated vaccine. The I-group 8b type fowl adenovirus Hexon protein inactivated by the triple inactivated vaccine is high in content, high in immunogenicity and low in formaldehyde content and endotoxin content, has better protection effects on current epidemic I-group 8b type fowl adenovirus, is good in safety properties and true in immune effects, can resist infection of clinical chicken groups on newcastle disease virusese, avianinfluenza and I-group 8b type fowl adenovirus, and is long in persistent period, the immunity persistent period can reach 5 months under the condition that 0.3mL of the vaccine is only used once, andat least 70% of the protection ratio can be provided for the chicken groups.