Disclosed are inhibitors of mevalonate pathway as an efficient vaccine adjuvant and use thereof. In particular, the inhibitor is an acetoacetyl-CoA transferase inhibitor, a HMG-CoA synthase inhibitor, a HMG-CoA reductase inhibitor, a mevalonate kinase inhibitor, a phosphomevalonate kinase inhibitor, a mevalonate-5-pyrophosphate decarboxylase inhibitor, an isopentenyl pyrophosphate isomerase inhibitor, a farnesyl pyrophosphate synthase inhibitor, a geranylgeranyl pyrophosphate synthase inhibitor or a geranylgeranyl transferase (I, II) inhibitor. Also disclosed is an immunogenic composition comprising inhibitors of mevalonate pathway as an adjuvant.