A two-year (2020 to 2022) research conducted at Prayagraj (Uttar Pradesh, India) in IRS farm of Sam Higginbottom University of Agriculture, Technology and Science to the Performance evolution of Aqua Crop model for mustard crop under residual method of energy balance. The experiment was plotted in random block design. This research work included 5 treatments with three replications. Under residual technique of energy balance, the first treatment subjected to more stress (at ???? ???????? =1.75) than the fifth treatment (at ???? ???????? =0.5 with a total irrigation depth of 420mm), second (I2 irrigation level ???? ????????= 1.5), third (I3 irrigation level ???? ????????= 1.0) and fourth (I4 irrigation level ???? ????????= 0.75) treatments received 240 mm, 300 mm and 360 mm of the design depth of irrigation water respectively. Among all irrigation scheduling, highest yield (2.23 t/ha), 1000 seed-weight (5.4g) and harvest index (24.3%) of mustard were found superior when irrigation was scheduled at ????????????= 1.5 with 240 mm depth of water. Maximum irrigation production 0.71 Kg/m3 (under residual method of energy balance at λET =1.5 with 240 mm of water depth) was recorded. Version 6.1 of the FAO aqua crop model was used to validate and simulate the harvest index, water productivity, biomass yield and yield of mustard for all irrigation scheduling. This model accurately simulates grain yield, biomass, and water productivity under for all irrigation scheduling of residual method of energy balance may be due to its good fit and good collinearity with observed data.