Erosion processes and modes may be changed on unpaved road formed by rolling original ground. The objective of this study was to reveal the changing mechanisms of water and sediment yield by a series of outdoor artificial rainfall simulation experiments in Shenfu coalfield. Results show that: (1) Flow regime is mainly the transitional flow on unpaved road and the laminar flow on original ground, and both of them are the subcritical flow. (2) Reynolds number, shear force, Froude number, flow velocity and stream power on unpaved road are higher than those on original ground, while the Darcy-Weisbach friction coefficient and the Manning roughness coefficient on unpaved road are lower than those on original ground. (3) Hydrodynamic parameters on unpaved roads are not absolutely consistent with those on original ground. (4) Sediment yield on original ground is lower than that on unpaved road and increased as runoff yield increases. (5) Correlation coefficients for the responsive relationships between sheet erosion rate and hydrodynamic parameters on unpaved road are in the following order: runoff kinetic energy> mean stream power> mean flow shear stress.