Abstract: Research on understorey of plantation in recent 20 years are reviewed. As one of the important ingredients in forest ecosystem, understorey takes important role in the plantation system that with simple structure, which interested the forest researcher at home and abroad. Those research focus on the understorey succession, the relationship between dominant species and understorey, the effect of understorey. Without disturbance, the succession sequence is: growth decay growth. The biomass, quantity, height and cover degree changes under different category and intensity disturbance. The relationship between understorey and dominant species appears in two aspects: they are cooperation and competition. The relevancy and complementarity of these three sections in understorey, improvement of biodiversity, and its hydrological function should be emphasized, at the same time, criterion system of evaluation of understorey function should be established.