Aiming at the problem of error caused by the tedious work of tabulation and chart in traditional foundation settlement calculation methods,based on the stratified summation method of the specification,Lagrange interpolation polynomial is used to fit the e-p curve of laboratory geotechnical test.Based on the original distribution function of additional stress p at soil depth z,the relationship function between foundation settlement s and soil depth z is established,and foundation settlement is calculated.The foundation calculation depth,stratified thickness and quantity are not limited,and the error caused by the calculation depth,stratified thickness,tabulation and graph in the traditional calculation is eliminated by this method which is simple and efficient,and has a good application value in the design work of foundation project.