Urbanization in China results in a large amount of abandoned land in hilly regions. Understanding the dynamics of plant communities in abandoned land under different utilizations will be helpful to efficiently manage and utilize such land. Theoretically, different uses of abandoned land might produce different light environments, which might influence the biomass and nutrient accumulation of herb communities in abandoned land. Developing plantations is a universal way of utilizing the abandoned land. As yet, little information is available about planted trees and their effect on the biomass allocation and nutrient accumulation of the herb communities in the abandoned land of the subtropical region. In order to understand the shifts of herb communities in the abandoned land after planting trees, therefore, the light environments under the plantation were simulated using a 50%-95% shading net, and the characteristics of biomass allocation and nutrient accumulation of the herb community under the simulated light regimes was investigated. The results showed that the total biomass of herb communities significantly decreased with the decreases of light intensity. Significant changes were observed in the aboveground biomass and its allocation proportion under shading treatments. However, the root biomass showed no significant changes compared to the control, and its allocation proportions significantly increased. There was a significantly positive correlation between light intensity and aboveground biomass. Under shading treatments, the carbon content significantly decreased in the aboveground part, but the contents of phosphorus and potassium significantly increased. However, the N content was not significant affected. The shading treatments significantly increased the contents of carbon, nitrogen, and phosphorus in root tissues, but only slightly influenced the potassium content. The proportions of carbon, nitrogen, phosphorus, and potassium allocation in the aboveground part significantly decreased with decreasing light intensity, but these values significantly increased in the roots. These findings reveal that the changes of nitrogen content in the aboveground part as well as the contents of carbon, nitrogen, and phosphorus in the roots were significantly related with light intensity. In addition, the ratios of carbon-to-nitrogen (C:N) and carbon-to-phosphorus (C:P) in the aboveground part were significantly decreased. No significant changes of N:P and C: P were observed, but the carbon-to-nitrogen (C:N) in the roots significantly decreased. These results suggest that shading mainly affects biomass and nutrient accumulation in the aboveground part of herb communities in abandoned land, but changes in the root are not sensitive enough for shading treatments.