[Purposes] This article aims to avoid the influence of temperature, temporary loads, and other factors on the cable force during the construction process of concrete-filled steel tube arch bridges and achieve precise and efficient control of the large-span arch bridges constructed by assembling cable-stayed buckles and hanging segments. [Methods] A control method is proposed to adjust the process state of arch bridges by replacing the the cable force with the unstressed length of the cable. The calculation formula for the unstressed length of the cable considering the sag effect and the tower deviation is derived, and the relationship between the increment of the cable force and the change of the unstressed length of the cable is studied. [Findings] The engineering calculation results show that the maximum error of cable force based on the unstressed state method is about 5%, and the maximum elevation deviation is 3.7 cm. The calculation accuracy meets the requirements, achieving precise and efficient construction control. [Conclusions] This method can eliminate the influence of temperature and temporary load changes on cable force, reduce the calculation workload of intermediate state of construction, and provide technical support for the assembly of large-span concrete-filled steel tube arch rib segments.