Abstract: A complex cap includes a coupling element, a shielding element and at least one filtering element. The coupling element has a first coupling part to be coupled with a neck portion of a bottle body, a recess formed in the first coupling part, and a first opening is formed in a bottom of the recess. The first opening is communicated with the mouth portion of the bottle body when the first coupling part is coupled with the neck portion of the bottle body. The shielding element is used for at least partially sheltering the first opening of the coupling element and comprises a second coupling part to be tight-fitted into the recess of the coupling element. The filtering element is mounted in the recess of the coupling element and arranged between the coupling element and the shielding element for filtering off external contaminants and controlling gas-permeable amount.