Abstract: Comprehensive analysis of productivity across different forest types and its affecting factors can elucidate the function and service mechanism of forest ecosystem, thereby providing scientific basis for promotion of forest management and conservation, and achievement of sustainable development goals. Based on multi-period monitoring data from 50 fixed plots (each 50 m × 50 m) across various forest types in Jiande Forest Farm in Zhejiang Province, this study illustrated differences among different forest types by utilizing species richness and species diversity indices (including the Shannon-Wiener index, Simpson index, and Pielou index), biomass and net productivity indicators, explored the direct and indirect factors affecting productivity of different forest types by adopting the structural equation modeling. The results revealed that significant differences existed in species richness, Shannon-Wiener index, Simpson index, and Pielou index of different forest types. These indices arose in a decreasing order: secondary broad-leaved forest after clear-cutting of Pinus massoniana > mixed coniferous-broadleaf forests > Cunninghamia lanceolata middle-aged forests> C. lanceolata mature forests. From 2021 to 2023, there were significant differences in biomass of different forest types, manifesting in the way of C. lanceolata mature and middle-aged forests > mixed coniferous-broadleaf forests > secondary broad-leaved forest after clear-cutting of P. massoniana. The net primary productivity (NPP) of different forest types varied from 2021 to 2022, with the secondary broad-leaved forest after clear-cutting of P. massoniana having the slowest growth, and the C. lanceolata middle-aged forests having the fastest growth. Elevation, soil and species diversity of woody plants had the direct impact on the NPP of different forest types, with the negative correlation between elevation and the NPP in the secondary broad-leaved forest after clear-cutting of P. massoniana. In both middle-aged and mature C. lanceolata forests, soil and woody plant species diversity were negatively correlated with the NPP, while the rest were positively correlated. Elevation, soil, and species diversity significantly affected the productivity of different forest types. The NPP of different forest type was collectively affected by multiple factors. This study elucidates the variation trend and driving mechanism of productivity across different forest types, offering reference for scientific formulation of forest management and conservation.