In large asphalt mixing plant, the matching accuracy and the measuring precision of the material are critical to the final asphalt mixture. This paper firstly deducts the mathematical model of the weighing system of large asphalt mixing plant. Then a genetic algorithms based iterative learning controller for the weighing system is designed. Finally, computer simulation and experimental study are performed. The results demonstrate well in terms of convergent speed and weighing precision. The proposed method could meet the need of the weighing system very well.