Abstract: Analysis of forest biodiversity dynamics in China is characterized by grey uncertainty caused by the paucity of relevant data and information, therefore, grey system theory may be helpful. Based on five surveys of the national Continuous Forest Inventory (CFI) in China during the period 1973–1998, we measured four indices with Pressure-State-Response (PSR) model, including Index of Forest Biodiversity (Ifbd), Index of Pressure on Forest Biodiversity (Ipr), Index of Forest Species Diversity (Isp) and Index of Forest Ecosystem Diversity (Ieco). The dynamics of forest biodiversity in the coming 10 years were also forecast with GM (1,1) grey models. The results predict that, in the coming two CFI periods (five years per CFI interval), Ifbd would continue increasing with accelerated speed compared with the last five CFI periods. In addition, Ipr would continue increasing, Ieco would fluctuate slightly, and Isp would continue increasing with moderate speed. The research suggests that grey forecasting model based on the PSR method is appropriate for forest resources management in China.