The invention discloses a suspension culture expansion method of serum-4 type fowl aviadenovirus. The suspension culture expansion method especially includes: inoculating virus of the serum-4 type fowl aviadenovirus identified through PCR (polymerase chain reaction) into chicken liver cells and efficiently expanding the serum-4 type fowl aviadenovirus with the cell suspension culture technology. The suspension culture expansion method of the serum-4 type fowl aviadenovirus is established by the aid of the chicken liver cells, effective expansion of the serum-4 type fowl aviadenovirus can be realized, and virus titer is more than 100 times higher than that of chick-embryo inoculation in virus culture (traditional chick-embryo toxicity titer is smaller than 10<6.0>TCID50/ml) as compared with chick-embryo inoculation; with the method, the technology for developing serum-4 type fowl aviadenovirus vaccines is provided, and good application value is achieved.