Extreme climatic events serve as key agents of change in environment-society systems, capable of triggering societal stress as well as fostering innovation and resilience. Nevertheless, systematic studies on human proactive responses to such shocks and the resulting social feedback mechanisms remain lacking. %OH-GDGTs records from Tianchi Lake in the Guanzhong Plain reconstruct the hydrological evolution of the Guanzhong Plain since 6.0 cal ka BP. By integrating regional paleoclimate records with archaeobotanical evidence, this study further elucidates agricultural adaptation strategies and environmental feedback mechanisms under prolonged arid Period. Since the mid-Holocene, an aridification trend affected the Guanzhong Plain, interrupted by three pronounced drought episodes at 5.6-5.4, 4.2-4.0, and 3.2-2.9 cal ka BP. Notably, the drought events around 4.2 and 3.2 cal ka BP coincided with floods caused by extreme rainfall. Confronted with persistent cold-arid conditions and demographic pressures, prehistoric communities transformed their predominantly broomcorn millet-based agriculture into a diversified, drought-tolerant cropping system by strategically cultivating wheat in fertile floodplains, thereby establishing an integrated "drought-flood" strategy that sustained regional agricultural prosperity and sustainability. This historical pattern deepens our understanding of ancient human-environment dynamics while providing valuable insights for contemporary agricultural adaptation and watershed management in arid regions.