Abstract:The calculation method of track settlement which caused by subgrade differential settlement, is based on continuous elastic point supported beam model. Then the method is put forward through introducing the nonlinearity boundary conditions of cosine-type subgrade differential settlement. And the corresponding C++ calculation programming is also worked out. Finally, the calculation method is applied to the actual engineering in western extended section of Shanghai metro line 2 of shield tunnel construction, which underpass Shanghai-kunming railway. The comparative analysis between the computation result and field measurement data is conducted. And it can be concluded that the calculation result can meet the actual measurement well. The calculation value of track settling tank width is as same as the measured value basically, and the calculated subsidence amplitude of track settling tank is slightly smaller than the measured value, but the difference is less than 1 mm (approximately 4% of track settlement value).