In order to find a method that can estimate the soil evaporation of gravel-mulched land in arid regions of central Ningxia effectively, the relationship between soil water evaporation ratio and surface soil water content under six sand-soil mixing ratios of 0 (S1), 20% (S2), 40% (S3), 60% (S4), 80% (S5), and 100% (S6) was studied, and the estimation model of soil evaporation of gravel-mulched land was constructed by setting up micro-lysimeters. The results indicated that the soil water evaporation ratio changed in stages with the surface soil water content, that was, S2~S6 had two stages, S1 had three stages, and there was a certain lag in the second and third stages of S1 compared with other treatments. The critical value of surface soil water content could be expressed as θ_si=0.0030s_i²-0.1705s_i+14.7340; The first and second stages of soil evaporation of S1~S6 could be expressed as E_s=E₀(a_iθ_i+b_i) and E_s=E₀(a_iθ_i²+b_iθ_i+c_i), respectively, (the second and third stages of S1 were E_s=E₀(a_iθ_i²+b_iθ_i+c_i)), and the overall accuracy was above 85%. Based on the above, the quadratic paraboloid model and polynomial model were constructed in two stages by further integrating water surface evaporation, surface soil water content, and sand-soil mixing ratios. The reliability of the model was high, and it could provide reference for local water resources management.