Forest restoration in the Three Gorges Reservoir Region (TGRR) is crucial for protecting ecological security of the reservoir. During the past 20 years, the implementation of two phases of Natural Forest Protection Project (NFPP I and NFPP II) was considered as a key role in restoring forest growth in the TGRR. Although the temporal dynamics of forest growth has been well recognized, the spatial stratified heterogeneity (SSH) of forest growth and its drivers are yet poorly understood, which, in turn, could hinder to implement furfure ecological projects and formulate proper policies in the TGRR region. In this study, the SSH patterns of forest growth (indicated by growing season Normalized Difference Vegetation Index, NDVI) during NFPP period and their potential driving factors (topographic, climatic and anthropogenic factors) in the TGRR were revealed by trend analysis method and geographic detector model. Moreover, the forests were classified into three stand origin types (primary forest, plantation forest and secondary forest) and four forest types (coniferous forest, broad-leaved forest, mixed forest and bamboo). We found that:(1) during the whole period of the NFPP, almost all forest area (97%) NDVI demonstrated an increasing trend. However, the growth rates of the secondary forests (in stand origin type) and bamboo (in forest type) were lower than those of other regions (0.0032/a vs. 0.0046/a). During NFPP II, the forest area with higher NDVI value and rapid growth increased significantly. (2) Overall, the most important main drivers of forest growth SSH were altitude and temperature during both NFPP I and NFPP II. During NFPP I, however, the population density and gross domestic product (GDP) density were detected as the most important drivers of forest growth SSH for plantation forests (in stand origin) and broad-leaved forests (in forest type). (3) The interactions of human activities (GDP density, population density and distance to built-up land) with altitude and temperature contributed more in explaining forest SSH. (4) Compared with the results of the NFPP Ⅱ, the joint effects of population density and GDP density on forest growth SSH decreased, while the effects of distance to built-up land on forest growth SSH increased. In addition, the study analyzed the effects of different drivers on forest growth SSH during the whole NFPP period. The results could enhance knowledge for implementing precise ecological projects and formulating forest protection policies in future.