The invention, which belongs to the field of radio technology, provides a broadband low-profile vertical polarization omnidirectional antenna with characteristics of antenna polarization size reduction and good broadband performance. The broadband low-profile vertical polarization omnidirectional antenna comprises a metal floor, a metal circular-truncated-cone-shaped sleeve, a round loading plateand a feeding coaxial line. The circular bottom surface of the metal circular-truncated-cone-shaped sleeve is fixed in the middle of the metal floor; an outer coaxial part of the feeding coaxial linepasses through the bottom of the metal floor and then is connected with the metal circular-truncated-cone-shaped sleeve; and the top of an inner coaxial part of the feeding coaxial line is connected with the round loading plate. In addition, the broadband low-profile vertical polarization omnidirectional antenna also includes short-circuit metal posts and open-circuit metal posts; the short-circuit metal posts enable currents of the round loading plate to be led to the metal floor in a short-circuit manner; and the open-circuit metal posts arranged on the metal floor are used for realizing opening circuit of the current of the metal floor. Because of loading processing on the top of the monopole antenna of the metal circular-truncated-cone-shaped sleeve, the broadband low-profile effect isrealized, so that the antenna has the good broadband performance.