The invention relates to the field of bridge construction, in particular to a construction method of an inverted-Y-shaped upper tower column closed section. A bridge tower is of a reinforced concretestructure, comprises two lower tower columns, two lower crossbeams, two middle tower columns, an upper crossbeam and an upper tower column, and is divided into 24 sections from bottom to top, whereinthe lower tower columns are arranged at the 1-4# sections, the middle tower columns are arranged at the 5-15# sections, the upper tower column is arranged at the 17-24# sections, the lower crossbeamsare arranged at the 4# section, and the upper crossbeam is arranged at the 16-17# sections and connected with the upper ends of the two closed middle tower columns. The bridge tower is constructed from bottom to top, a rolling over construction process and a hydraulic formwork creeping construction process are reasonably and organically combined for construction aiming at the reality, the construction period is shortened, the overall strength of the bridge tower is improved, the mechanization degree is high, construction is safe, wind resistance is high, the concrete appearance quality is significantly improved, and a construction site is civilized and clean; and during engineering, a concrete body is high in strength, and few in surface defect, and has good performance of resisting external erosion and temperature difference change, durability and anti-cracking performance are excellent, and the long-term engineering quality is guaranteed.