Abstract:The applicability of the Curve Number Method (SCS-CN) in different land use patterns was discussed to provide some references for the evaluation of water and soil conservation measures by this method. Based on the monitoring data of runoff plots in semi-arid areas of Northeast China, the feasibility of SCS-CN method in evaluating soil and water conservation measures and tillage methods was analyzed by the methods of simultaneously calibrating of runoff curve number (CN) and the initial loss ratio. The results showed that:(1) Under the drought (AMC1) condition, the optimal value of λ was 0.05, but the simulation results of different land use patterns was not ideal, while the results of bare land, contour ridge and ridge along slope simulated by the modified method of the potential maximum retention (S) were better, and the corresponding CN1 values were 87.54, 68.49 and 60.46, respectively, and the optimal value of λ was 0.40. (2) The results of horizontal troughs, vegetation belts and terraces were not ideal, and the calculated values were too large when the measured runoff was more than 10 mm. The simulation accuracy was greatly improved through correcting by runoff coefficient ratio, which was recommended as a suitable correction method for water conservation measures. (3) Under normal (AMC2) and wet (AMC3) conditions, the amount of data was limited, keeping the optimum value of λ remained, correcting S value, the simulation result was ideal, and it was a suitable estimation method for arid areas.