Arid regions, covering approximately one-third of Earth's land surface, are highly sensitive to climate change. In recent years, Central Arid Region of Asia (CARA) has exhibited a significant "warming and wetting" trend. However, the mechanisms governing the source of this increased precipitation remain controversial. This study integrates long-term observations of stable isotopes in precipitation from multiple stations spanning 1970 to 2022 to systematically analyze the driving mechanisms behind the precipitation increase in CARA. The results indicate that: (1) Despite a significant rise in regional air temperature, stable isotopes in precipitation show a marked long-term depletion trend (-1.10 parts per thousand/decade for delta 18O). This suggests that precipitation variability is controlled to a certain extent by changes in moisture sources rather than solely by local thermal processes. (2) Analysis of atmospheric circulation reveals that changes in circulation systems controlling the region have significantly enhanced high-latitude meridional moisture transport originating from the Arctic and the North Atlantic. The Rayleigh fractionation effect during long-distance transport is the dominant factor leading to the depletion of precipitation isotopes. (3) Despite increased high-latitude input, annual-mean d-excess remains stable, reflecting synchronous intensification of local moisture recycling that offsets external depletion. These findings confirm that CARA precipitation increase is co-driven by enhanced external high-latitude moisture transport and intensified local recycling, providing observational constraints for improving moisture transport representations in regional climate models and supporting adaptive water resource strategies in Central Asian arid zones. Significance statement: The "warming and wetting" trend in Central Arid Region of Asia poses a critical puzzle for water security and climate modeling. By synthesizing a 53-year (1970-2022) record of precipitation isotopes, we resolve the mechanisms behind this trend. We reveal that the precipitation increase is not driven solely by local thermodynamics, but by a synergy of enhanced high-latitude moisture transport and intensified local moisture recycling. This work highlights the dynamic balance between external moisture advection and internal landatmosphere coupling, providing critical observational constraints for correcting biases in climate-model simulations and improving projections of the Asian water cycle.