Recently, with the rapid development of the high-speed railway in our country, the long-term settlement of the soft soil subgrade subjected to train load has attracted our attention. In this work, the application of constitutive model method, experiment model and the machine learning method on the calculation and prediction of the settlement of subgrade was reviewed briefly. The investigation shows that the unified recognition to the train load was not formed. The influence of modulus softening of the subgrade subjected to the train load on the longterm settlement of subgrade are not considered, and the influence of the load harmonic was also not considered.