Global climate change will have a huge impact on future food production. Water and temperature are the most important environmental factors in the growth of winter wheat and summer maize, which significantly affect their yield. Based on the irrigation experimental data of winter wheat and summer maize in Baoding Irrigation Experimental Station in North China Plain from 2006 to 2015, the AquaCrop model was calibrated and validated, offering crop growth process simulations following local conditions. Being similar in structure of the four typical water production functions ( Blank model, Stewart model, Jensen model, Minhas model), the water-heat production functions were set up between accumulated temperature, water consumption, and yield at each growth stage of winter wheat and summer maize. Using the data from the sixth version of the model for interdisciplinary research on climate (MIROC6) of the commentary on the coupled model intercomparison project (CMIP6), the daily rainfall and temperature data were downscaled to consider future climate change, including low carbon emission forcing scenario SSP1 RCP2.6 and SSP4 RCP3.4, medium carbon emission forcing scenario SSP2 RCP4.5, medium to high forcing emission scenario SSP3 RCP7.0 and high forcing scenario SSP5 RCP8.5. On this basis, the yields and their changes for winter wheat and summer maize in 2024—2064 were obtained and analyzed by the presented water-heat production function. Results showed that the AquaCrop model made good performances to simulate the growth process of winter wheat summer maize in this region after its calibration and verification by using ten years of irrigation test data. Among the four kinds of water-heat production functions constructed by the verified AquaCrop model simulation data, the Jensen type function had the highest output simulation accuracy. According to the water-heat production function, winter wheat was most sensitive to water during heading filling stage, and accumulated temperature during greening jointing stage had the most obvious effect on yield. Summer maize was most sensitive to water in jointing and heading period, and the accumulated temperature in this period had the most obvious effect on yield. Under the emission scenarios of SSP1 2.6, SSP2 4.5, SSP3 7.0, SSP4 3.4, and SSP5 8.5 in the five future climates, the potential yield of winter wheat tended to fluctuate, but it was higher than the current average potential yield. By the 2050s, the average potential yield of winter wheat would be 6.07 t / hm 2 , 6.26 t / hm 2 , 6.93 t / hm 2 , 5.74 t / hm 2 , and 5.95 t / hm 2 , respectively. The overall potential yield of summer corn was on the rise, and by 2050s, the average annual potential yield of summer corn would reach 9.27 t / hm 2 , 9.20 t / hm 2 , 9.05 t / hm 2 , 9.10 t / hm 2 , and 9.24 t / hm 2 , respectively. Overall, winter wheat and summer corn were more suitable for growth and development under SSP3 7.0 and SSP1 2.6 scenarios, respectively. Considering the hydrothermal conditions, the potential yield of winter wheat fluctuated down under the five climate scenarios, while the potential yield of summer maize showed an overall upward trend. Supplementary irrigation can bring about 70% of contribution rate to the potential yield of winter wheat. The contribution rate of rainfall during the growing period to the potential yield of summer maize was about 94% . The results can be used to evaluate the change of crop grain yield in this region under future climate change, and provide theoretical basis and technical support for the national strategy of ensuring food security.