Arid Central Asia, located far from major oceanic moisture sources, represents a typical dryland region that is highly sensitive to climate change. However, the characteristics and driving mechanisms of regional hydro-climatic variability at decadal-centennial timescales over the past millennium remain debated, largely due to the scarcity of high-resolution records. In this study, a sediment core from Lake Jing in the southern Tianshan Mountains was investigated. A chronological framework was established using 137Cs and AMS 14C dating. Based on XRF elemental scanning, grain-size analysis, and end-member modeling, we reconstructed the hydroclimatic variability of arid Central Asia over the past 900 years and explored its potential driving mechanisms. The results indicate that a flood event occurred in the study area around 1958 CE, which is consistent with the historical record. On centennial timescales, the climate was relatively dry during the late Medieval Warm Period (MWP) and the Current Warm Period (CWP), but relatively wet during the Little Ice Age (LIA). Since the LIA, the regional climate has shown significant variability. Relatively humid periods occurred during 1390-1450 CE, 1550-1630 CE, 1690-1760 CE, 1810-1900 CE, and from 1950 CE to the present, corresponding to the negative phase of the North Atlantic Oscillation (NAO). In contrast, relatively dry conditions occurred during 1450-1550 CE, 1630-1690 CE, 1760-1810 CE, and 1900-1950 CE, corresponding to the positive phase of the NAO. Spectral and cross-wavelet analyses further reveal that regional hydroclimatic variability exhibits a significant 90-120-year periodicity associated with the Gleissberg solar cycle on centennial timescales, as well as a prominent 20-30-year oscillation linked to the NAO. These results suggest that centennial-scale solar forcing and decadal variability of the NAO jointly drove the hydroclimatic changes in arid Central Asia during the past 900 years.