Abstract: A new method is presented for the settlement calculation of composite ground with rigid piles, taking into account the pile-soil-cushion interaction mechanism. The relationship of skin friction and relative displacement between the pile shaft and the surrounding soil is idealized as perfectly elasto-plastic. Settlement of soil at the same depth is assumed to be equal and the soil at the pile tip is considered to behave the same as Winkler ground. The governing differential equations are derived through analyzing the pile-soil-cushion interaction and formulas for the settlement calculation are then obtained. Two case studies of nine-pile composite ground are made, which show that the predictions given by the derived formulas agree reasonably well with field measurements as well as with finite element results.