To effectively analyze characteristics of fluid phase in unsaturated zone, this paper solved the diffusance based on Gardner model for relative hydraulic conductivity, deduced the analytical solution for one dimensional fluid phase motion equation in unsaturated zone, and proposed the evaporation front depth model, the effective saturation profile model of hydraulic connection area between the homogeneous and layered soils, and the hydraulic parameters inversion calculation model. The results showed that the effective saturation profile of unsaturated soil under steady flow is affected by specific discharge q, Gardner model parameters αg and the variabilities of water head of the lower boundary h. The effective saturation profile and evaporative front depth of upper soil in stratified soil are affected by the permeability of lower soil. Parameter inversion analysis verifies the reliability of analytical solution of liquid phase motion equation.