With indoor artificial rainfalls, effects of cultivation measures on runoff were determined from lands with surface different in roughness as a result of different cultivation measures. The results showed that runoff decreased with the increase in surface roughness, thus leading to reduced erosion. Based on the results, a calculation equation was established accordingly, providing a useful tool for further consummating the model for predicting soil erosion and a theory basis as well for harnessing soil and water loess and restoring forests and grasslands on unsuitable farmland in the Loess Plateau.