Background and Objectives Predicting of maize yield response to climate change : Case Study Cambodia The 2nd International Symposium on Conservation and Management of Tropical Lakes Raksmey Na, Camilla Vote, Chantha Oeurng, Layheang Song Faculty of Hydrology and Water Resources Engineering, Institute of Technology of Cambodia, Cambodia Background and Objectives Statistical Indicator and their Evaluations  Agriculture is an essential sector which Cambodian subsistence heavily depends on, plus it is the first priority of the government’s development strategies since 1993 (CDRI, 2011).  In Cambodia: 54.2% employed in, 32.6% land area devoted to, 36.7% share of agriculture in GDP (FAO, 2017).  Yet traditional agricultural techniques and seeds are still widely used, farming is predominantly rainfall dependent, and most farmers grow only one crop a year (namely Rice). Result and Discussion  Understanding the connection between the stress of water on crop yields and impacts of future climate change is essential for making proper management decisions for crop production. Simulation Results of Canopy Cover (CC), Biomass (B), and Yield (Y) & Soil Water Content (SWC)  The primary objectives of the research are listed below: Calibrate the AquaCrop model to effectively simulate historical crop yields in 2016 planting on the field in Phnom Penh, maize, at CARDI as the baseline. Simulate future predictive crop yields using three GCMs with one emission scenario RCP 6.0 along 2050s to understand the climate change impacts on crop yield. Materials and Methods AquaCrop Model  Crop Water Productivity Model “Aquacrop” (Raes et al., 2015): Simulate crop response to environmental change by comparing attainable and actual yields in a regular field. Identify the constraints limiting crop production and water productivity. Maximize water productivity under water deficit conditions through irrigation strategies & crop and management practices. Study the effect of climate change on food production. AquaCrop Version 5.0 Framework of Modeling Processes Projected Climate Input Data Projected B & Y Crop Data Climate Parameters DAS: Days After Sowing Soil Profile Irrigation Application Conclusion AquaCrop model performance is good in the environment of Cambodia since the Biomass and Yield are effectively acceptable with the very good result . AquaCrop works effectively with the herbaceous crop. The projected results show to decline for the maize yield in the future significantly. The affects from the climate change on crop yield should be the approach for mitigation, preparedness, and resilience strategies to the stakeholders of crop cultivation. Link to Generate the Projected Climate Observed Data Date Day Numbers Observed Value 8-Feb-16 19 14 11-Feb-16 22 11 15-Feb-16 26 27 18-Feb-16 29 32 23-Feb-16 34 60 25-Feb-16 36 1.37 14-Mar-16 54 3.56 8-Apr-16 79 9.90 Canopy Cover (%) Biomass (t/ha) Acknowledgment This research is supported by Australian Center for International Agricultural Research (ACIAR) as “SMCN/2012/071”.