| Active grille shutter can control vehicle front-end opening area, thereby the fuel economy will be improved. The control of grille angle and fan speed under different vehicle driving conditions is a difficulty in the research of active grille shutter. Firstly, the accuracy of both computational fluid dynamics simulation and engine cooling system one-dimensional model were verified by wind tunnel tests and numerical simulation separately. Secondly, an approximate model considering the AGS angle, cooling fan speed, vehicle speed and drag coefficient, cooling air velocity was constructed by optimal Latin hypercube sampling and neural network fitting method, and then the model was input to the cooling system model. According to the real-time engine cooling demand, the AGS angle which can both meet the cooling requirements and minimum drag coefficient was chosen out. Finally the fuel reduction ratio of 0.6%~0.7% could be achieved under different ambient temperatures.