The invention discloses an upper transverse beam and lower transverse beam construction method for a bridge tower. The method comprises the following steps: before normal construction, constructing hanging systems, tensioning first hanging systems on both sides of the tower respectively, and tensioning two groups of second hanging systems between the first hanging systems, wherein adjacent first hanging systems and second hanging systems can operate in a matching way or operate independently; performing upper transverse beam construction, constructing and pouring a first-segment side form, a second-segment side form and a third-segment side form, and constructing and pouring an upper transverse beam bottom form; after completion of upper transverse beam construction, pouring a lower transverse beam which is formed by means of prefabrication, performing transportation and installation through the hanging systems, and finally connecting an upper transverse beam with the lower transverse beam. Through adoption of a bracket-free construction technology, the construction cost is reduced, the construction period is shortened, and the construction safety is enhanced; the upper transverse beam and the lower transverse beam are constructed stepwise, so that the construction difficulty is lowered. Meanwhile, the upper transverse beam and the lower transverse beam are constructed stepwise, so that the construction difficulty is lowered, and the construction quality is enhanced.