In order to study the effect of different fertilizer concentration (Urea) on soil hydraulic parameters,the sandy loam of three-stage terrace and clay loam of the first terrace in Yangling District of Shaanxi Province are used as the test soil,the parameters of soil hydraulic under different fertilizer concentration were estimated by numerical inversion method,and analyzes the influence of the change of soil hydraulic parameters on the cumulative infiltration quantitatively,Finally,the estimation formula of soil hydraulic parameters considering the change of fertilizer concentration was established. The results showed that with the increasing of fertilizer concentration,the saturated water content (θ_s),shape coefficient (n) and saturated hydraulic conductivity (K_s) of soil is increasing,but the suction of intake reciprocal value (α) decreased with the increasing of fertilizer concentration. The sensitivity of soil hydraulic parameters to cumulative infiltration is n > θ_s > K_s > α,and the influence of α on cumulative infiltration is less than 10%. In this paper,the relationship between θ_s and K_s and the concentration of fertilizer solution is exponential function. Utilizing estimation result simulated the cumulative infiltration amount and water content of soil profile in the process of one-dimensional vertical infiltration,and compared with the measured value,the two are showing no difference,It shows that the formula of soil hydraulic characteristic parameters considering the change of fertilizer concentration is reliable,this study can provide theoretical basis for water and fertilizer management of farmland.