The construction technique for closing the central span and side spans of a steel box girder cable-stayed bridge was described. The bridge is part of the Xiamen-Zhangzhou Sea-Crossing Bridge and has a main span of 780 meters. The method used for closing the girder sections over the auxiliary and transitional piers involved cantilever assembling construction. For the central span closure, a match-cutting method with incremental launching was used to account for temperature and launching force effects. Throughout the construction, an unstressed state control method was employed for monitoring and control.