[Objective] The dynamic mechanism of soil erosion on vegetation covered slope was studied in order to provide theoretical support for revealing the mechanism of vegetation covered slope erosion in earth rock mountainous areas of North China. [Methods] Based on the runoff dynamic characteristics of slope and the method of artificial rainfall simulation, the relationships between runoff hydrodynamic characteristics and erosion processes on vegetation covered slopes (Pinus tabuliformis, Platycladus orientalis, Quercus variabilis and Ziziphus jujuba) were explored quantitively. [Results] The Platycladus orientalis covered slopes had the greatest runoff yield amount with mean value of 56.85 L. The Quercus variabilis covered slopes had the greatest sediment yield amount with mean value of 1 189.15 g. Runoff velocities under all 4 kinds vegetation ranged from 0.803±0.213 to 4.276±0.430 m/min. Reynolds number and Froude number increased with the increase of rainfall intensity, and the values varied 7.127～63.630 and 0.177～0.900, respectively. [Conclusion] Vegetation cover on the slope has a good effect of reducing runoff and sediment. The dynamic factors of runoff on slope are closely related to the sediment yield, which is an important factor to predict the process of soil erosion.