Climate change threatens agriculture, making arid regions vulnerable to overgrazing, crop encroachment, and shifting climate parameters. Stipagrostis ciliata (S. ciliata), a drought-resistant perennial grass, plays a crucial role in restoring semi-arid and arid rangelands and combating desertification. This study parameterized, calibrated, validated, and tested the LINTUL-MULTICROP model to assess S. ciliata biomass responses under three global climate models (GFDL-ESM2M, HadGEM2-AO, and MPI-ESM-MR). Model calibration and validation showed strong correlations between observed and simulated biomass (R2 = 0.985 and 0.981, respectively), with statistical assessments confirming satisfactory performance (nRMSE = 14.70%, MAE = 0.648 t ha-1, p = 0.92, d-index = 0.994). Climate change simulations under RCP4.5 and RCP8.5 projected increasing biomass across future periods, peaking at 14.6 t ha-1 in 2080-2099. The results highlight S. ciliata's potential in climate adaptation, emphasizing its role in enhancing biomass productivity while raising concerns about biodiversity conservation. The validated LINTUL model provides a reliable tool for predicting ecosystem responses in arid environments, supporting sustainable land management and rangeland restoration strategies amid evolving climate challenges.