At present, the research on one-dimensional nonlinear consolidation of soft soil rarely considers multi-stage loading, but multi-stage loading is a common loading form. In order to study the one-dimensional nonlinear consolidation law of soft soil under multi-stage loading, a consolidation model considering both soil nonlinearity and multi-stage loading was established. The finite difference method was used to solve the consolidation equation, and the correctness of the proposed solution was verified by comparing with the existing solution. Furthermore, the influence of load form and nonlinear parameters on the consolidation characteristics of soil was analyzed. The results show that compared with instantaneous loading or single-stage loading, multi-stage loading can fully dissipate the excess pore water pressure of soil and reduce the peak value of excess pore water pressure. Because the first stage load has the greatest influence on the consolidation of soil, the loading amount and loading rate of the first stage load should be controlled to avoid the damage of soil when the multi-stage load is used in engineering.