The invention relates to the field of bridge engineering foundation structures, and provides a bridge tower structure and a construction method thereof. The bridge tower structure comprises two groupsof caisson pile foundation groups, wherein each group of caisson pile foundation groups comprises more than two caisson pile foundations, a bearing platform is arranged on each caisson pile foundation, and the adjacent caisson pile foundations in each group of caisson pile foundation groups are fixedly connected through tie beams. The bridge tower structure further comprises two tower columns which are fixedly connected with each other in an inverted Y shape, each tower column comprises a plurality of tower column sections which are sequentially spliced, and the lower end of each tower columnis fixedly connected with the two bearing platforms on the outer side of one groups of the caisson pile foundations. The bridge tower structure and the construction method thereof can solve the problem that in order to meet the large bearing requirement of the bridge tower structure, the cross-sectional area in the central axis direction of a bridge is increased, so that the increase of the self-weight of the bridge tower and the increase of the foundation cost of the bridge tower are caused.