Electroosmotic consolidation can be used as an efficient technique for soft soil improvement. Considering the limitation in previous theories that soil parameters keep constant during electroosmotic consolidation, the nonlinear relationships between soil compressibility, hydraulic and electroosmosis conductivities, and void ratio are incorporated in a one-dimensional model in the present study. The analytical solutions for the ultimate excess pore-water pressure and surface settlement are derived. A comparison between the proposed analytical solutions and traditional theory indicates that the nonlinear variation of hydraulic conductivity results in a larger ultimate excess pore-water pressure, whereas the nonlinear variation of electroosmosis conductivity leads to a smaller one. The effects are more significant for soils with higher compressibility. The nonlinear variation of soil compressibility exhibits remarkable impact on the development of excess pore-water pressure when the nonlinear variations of hydraulic and electroosmosis conductivities are considered. Compared with the ultimate excess pore-water pressure, the impact of nonlinear variations of soil parameters on the ultimate surface settlement is less significant.