Groundwater fluoride enrichment in arid regions involves complex natural-anthropogenic interplay. The longterm irrigation has created complex dynamics by altering groundwater hydrological and hydrochemical conditions. However, the quantitative contributions of specific geochemical processes and the precise impacts of irrigation practices on Fenrichment remain inadequately quantified. This study established a hydrochemical mass balance equation to quantify the contributions of key processes governing Fenrichment dynamics, including mixing, evaporation, mineral dissolution, and adsorption/desorption, supplemented by Natural Background Level assessment and hydrogeochemical simulations. Results revealed a distinct east-west zonation of groundwater fluoride, which had low-F-(<1.0 mg/L in 82 % samples) in the western part (Zone I) and high-F(>1.0 mg/L in 56 % samples) in the eastern part (Zone II). The NBL of Fwas significantly higher in Zone II (loess terrain: 1.54 mg/L) than Zone I (alluvial-pluvial deposits: 0.6 mg/L), confirming geologic dominance. However, intensive irrigation substantially reduced groundwater Fby 30-70 %, with reduction magnitude governed by irrigation quota, aquifer permeability, and thickness. Furthermore, processes controlling Fvariation along flow paths shifted from dilution-dominated in recharge areas (-67.2 %) to cation exchange-dominated in runoff zones (+68.8 %), and finally to evaporation-adsorption interactions in discharge areas. Irrigation mixing promoted precipitation/dissolution of calcite, dolomite, and gypsum, modulating Ca2+ activity and consequently fluorite equilibrium. This study establishes a novel quantitative framework linking geogenic Fenrichment and irrigation-induced dilution, providing more insights into groundwater management in arid farmlands.