Under same grazing conditions, the vegetation stability on pastureland with trees in higher than that on natural pastureland. The dominant plants are growing in groups, and undominant species are distributed randomly and scatteredly. In each grazing circle from inner outward, vegetation variation decreases progressively. Furthermore, because of the different carrying capacities of pastures, stages of light->suitable->heavy->strong grazing on pastureland with trees and suitable (light)->heavy->strong->extreme grazing on natural pastureland occur in all grazing circles.