Abstract: Based on an analysis of the developing mechanism of composite foundation settlement in combination with the characteristics of Verhulst gray model, a Verhulst gray model for the composite foundation settlement was specially developed to reflect the characteristics of settlement-time curve, such as its monotone increasing, boundedness and S-shape. The precision check proved that by such a Verhulst gray model less observing data are required to set up a prediction model with reliable precision through a mathematical reasoning process, which will reveal the long settlement process of composite foundation.