Abstract: Based on the advantages of clear load transfer, light self-weight, and strong spanning capacity, steel truss bridges have been widely used in railway, highway, and municipal bridge engineering. The incremental launching method has become a common construction technique for such bridges due to its low environmental impact, strong terrain adaptability, and high efficiency and safety. However, during the incremental launching process, the load-bearing system undergoes frequent transformations, resulting in complex and variable structural responses, and quality control of a single stage is insufficient to ensure the accuracy and safety of the final bridge state. To address this, taking the steel truss bridge of the Qingchuang Avenue crossing over Junhe Chong as the engineering background, this paper proposes a closed-loop quality control system comprising "simulation prediction-monitoring point layout-real-time comparison-dynamic warning-graded response." In contrast to existing studies that focus on individual stages, this system achieves multi-parameter dynamic feedback and quantitative deviation analysis between measured and theoretical values throughout the entire launching process. By establishing a finite element model and conducting synchronous monitoring of deformation and stress, the proposed system is employed to perform real-time deviation assessment and graded response for structural responses under various construction conditions. The results show that under all launching stages, the maximum measured lateral displacement is 90  mm, the maximum vertical displacement is 105  mm, and the maximum structural stress is 66.6  MPa, all of which satisfy the design requirements. The measured values generally follow the same trends as the theoretical values, with local deviations all maintained within the warning thresholds and no over-limit alarms triggered. This verifies the effectiveness of the closed-loop control system in deviation identification and dynamic regulation during construction, and provides a reference and methodological guidance for quality control of similar steel truss bridge incremental launching projects.