Study region: This study focuses on mainland China, where regions are classified into arid, sub-arid, sub-humid and humid types based on the aridity index (AI) thresholds. Study focus: This study quantified the combined effects of climate change and vegetation restoration (1982-2020) on Terrestrial Water Storage Anomaly (TWSA) using partial least squares structural equation modeling (PLS-SEM). We analyzed spatiotemporal trends and partial correlation relationships of TWSA and its related climate and vegetation variables, and evaluated direct and indirect pathways influencing TWSA across different climate zones. New hydrological insights for the region: (1) TWSA showed an overall decline of-0.267 cm/a, with notable decreases in southeastern Tibet, North China, and the Ili River Basin, whereas increases occurred in South China, the Songhua River Basin, and northern Tibet. (2) Since 2000, accelerated vegetation greening exerted heterogeneous impacts on TWSA. In arid/ sub-arid regions, initial vegetation expansion improved water retention, but exceeding local water carrying capacity ultimately led to net water loss. In humid/sub-humid regions, greening promoted water conservation, benefiting TWSA in humid regions and mitigating its decline in sub-humid regions. (3) Climate change influenced TWSA directly or indirectly through vegetation change. Precipitation was the primary positive driver, with its effect amplified by vegetation dynamics in humid/sub-humid regions but dampened in arid/sub-arid regions. Rising temperatures exerted a negative indirect effect on TWSA, with amplified effects in arid/sub-arid regions post-2000 but diminishing impacts in humid/sub-humid zones.