The invention relates to a round steel tower structure of a bridge and effectively solves problems that the round steel tower causes tensile deformation easily when being in the same plane with the bridge and the like. According to the technical scheme, the round steel tower structure comprises a bearing platform and is characterized in that a tower base located in the center of the bridge is fixedly connected onto the bearing platform, a round steel tower divided into multiple sections is connected onto the tower base, and the round surface of the round steel tower is parallel with the direction of the bridge. The round steel tower structure is reasonable and standard, so that the round steel tower structure cannot cause tensile deformation in the same plane with the bridge floor and can well keep the round structure, bear transverse tension of steel cables on the bridge floor and completely play a due role of a steel tower of the bridge.