A lid of a disposable beverage cup, which has at least one drinking hole provided for a consumer to drink the beverage stored in the beverage cup, and at least one vent hole provided for maintaining the pressure equivalence between an inner side and an outer side of the beverage cup, includes at least one drinking hole plug arranged for detachably coupling with the drinking hole to seal and close the drinking hole so as to prevent the beverage from leaking out of the beverage cup.