Abstract: The tangent modulus method proposed by YANG Guang-hua is simple, with few parameters and easy for engineering application. The researches have shown that it has better accuracy when calculating the foundations with conventional dimensions, but for the large-sized foundations such as rafts, the calculated settlement is too large. For this reason, an advanced tangent modulus method considering the increase of the initial tangent modulus extension depth is proposed. The comparison with the actual engineering case and the calculated results by the finite element method of the small-strain hardening soil model shows that the advanced tangent modulus method can be more realistic. This further develops and improves the tangent modulus method.