Abstract: Loading devices and displacement and stress measurement systems are installed on the geotechnical centrifuge. A centrifugal model in line with the actual stress is established. Considering different conditions, the treatment techniques for new and old roadbeds as well as the improvement efficiency of prestressed pile composite foundation treatment in differential settlement deformation of road widening are studied. The differential deformation features of the widening project and the effectiveness and mechanism of the treatment techniques are simulated. The results show that for the road widening laid with geotextile materials in different strata, although uneven settlement of new and old roadbeds may reduce, the effeciency is not obvious. With the help of reinforced treatment, the lateral displacement of shallow soil greatly decreases, while that of deep soil changes little, indicating that the reinforcement has limited effect on the lateral displacement of soft soil, Using prestressed pipes to handle road widening can control the uneven settlement, greatly accelerate the construction schedule and shorten the construction period, indicating that the composite piled foundation in soft soil is suitable for road widening projects with urgent construction time and high settlement control requirements. The study also shows that the pipe piles produce upward penetration deformation, and due to pile caps and reinforced cushions, the penetration depth is effectively alleviated.