Context: The arid region of western Inner Mongolia is an important maize production area in China, where severe water scarcity necessitates a shift from water-consuming conventional irrigation to water-saving and efficient irrigation. Objective: This study aims to use the DSSAT model to develop an optimized drip irrigation strategy for further improvement in water-saving and water use efficiency in this region. Methods: The DSSAT model was first calibrated and validated using data obtained from field experiments and literature in Bayannur district in this arid region. Next the validated model determined the lower threshold of the relative soil water content (RSWC) as the indicator for triggering re-irrigation. Then, the appropriate single irrigation rate for different growth stages were determined through simulation experiments with the premise of the lower threshold of RSWC. Subsequently, the model-optimized irrigation strategy (MOI) was proposed and verified by the field experiment and long-term meteorological years' simulations. Results and conclusion: The lower thresholds of RSWC were found to be 45 %, 70 %, 75 %, and 20 % during four growth stages, including GS1 (from sowing to the 6-leaf stage), GS2 (from the 6-leaf stage to tasseling), GS3 (from tasseling to R3 stage), and GS4 (from R3 stage to maturity), respectively. The appropriate single irrigation rates were determined as 375, 450, 375, and 225 m3 ha-1 at GS1, GS2, GS3 and GS4, respectively. The field experiment revealed that the MOI strategy significantly increased yield and saved 25.4 % of irrigation water in comparison with the farmer's drip irrigation strategy (FDI). In addition, a comparative simulation of MOI and FDI using 23-year's meteorological data (2000-2022), showed that the simulated yields of MOI and FDI were comparable, but MOI saved 27.6 % of irrigation water and significantly increased irrigation water use efficiency by 40.3 % averaged across 23-year. Significance: This study's model-optimized drip irrigation strategy proposed in this study had a high water-saving potential by fully using precipitation and real-time controlling irrigation.