Abstract: The reinforced-gravel-pile composite ground is a new method for treating soft soil ground. Based on the in-depth studies on the deformation mechanism for reinforced-gravel-pile composite ground under flexible foundation, firstly, according to different relative slips between the gravel piles and the soil around them, the reinforced area can be divided into reinforced-gravel-pile zone, unreinforced-gravel-pile plastic zone and unreinforced-gravel-pile elastic zone. A model for analyzing the settlement of the reinforced-gravel-pile ground under flexible foundation is established. Afterwards, according to different deformation mechanisms in different zones, the corresponding deformation analysis methods for various zones are established. Consequently, a new settlement analysis method for the reinforced-gravel-pile composite ground under flexible foundation is developed. The proposed method can consider the influences of relative slip between pile and soil, and reflect the influences derived from the lateral deformation of gravel piles in the unreinforced-gravel-pile elastic zone. Finally, the proposed method is applied to a practical project. Compared with the other existing methods, the proposed method is more feasible and reasonable.