<p>In the loess region of northwest China, a large number of high—fill projects have emerged. The calculation of foundation settlement in high—fill sites is of great significance for engineering construction. Firstly, this paper proposes a mathematical model to represent the stress—strain of compacted loess. Based on the layer—wise summation method and the secant modulus method, a calculation model for high—fill foundation settlement is established. The relationships between moisture content, compaction degree and secant modulus are studied, and the corresponding expressions are obtained. The influences of factors such as filling height, initial moisture content and compaction degree, and the changes in moisture content and compaction degree of soil layers at different depths of the filling body on the settlement of the filling body are analyzed. The research results show that both the compaction degree and the moisture content have a significant impact on the settlement of high—fill. Comparatively, the impact of the compaction degree is more prominent. When the moisture content of the filling body is higher than the optimum moisture content, its impact on the settlement of the filling body is more significant than when the moisture content is lower than the optimum moisture content. When the compaction degree of the surface soil of the original foundation and the soil layers at relatively deep parts of the filling body is high, the settlement of the filling body will decrease. In addition, as the height of the filling body increases, the proportion of the settlement of the original foundation in the total settlement gradually decreases, generally not exceeding 30%. The research results of this paper have certain reference value for the design of high—fill loess sites, the calculation of foundation settlement and the control of post—construction surface settlement.</p>