The invention relates to an application of a
cerium oxide nano-material in a
vaccine adjuvant and / or a vaccine inactivator, in particular to a vaccine, when the
cerium oxide nano-material is the
vaccine adjuvant, the vaccine comprises the
vaccine adjuvant and an
immunogen; or when the
cerium oxide nano material is a vaccine inactivating agent, the vaccine is a composite vaccine, the composite vaccine comprises the vaccine inactivating agent and a
virus, and the
virus is embedded in the
cerium oxide nano material; the preparation method of the composite vaccine comprises the step of mineralizing and inactivating viruses by using a vaccine inactivator, wherein the vaccine inactivator is cerium salt. The
cerium oxide can be used as a vaccine
adjuvant and also can be used as a
virus inactivator. The maturation of dendritic cells and macrophages can be promoted by means of regulating the level of
active oxygen in immune cells and the like, and the
antigen presentation efficiency is improved, so that the vaccine-induced
body fluid and cellular immune response is enhanced; meanwhile, cerium salt can directly act on virus
surface protein for mineralization, efficient and safe
virus inactivation is achieved, and preparation of inactivated vaccines is facilitated.