The uncertain factors and their effects on system operation are comprehensively explained in this paper, of which the laws of wind and load prediction errors on different time scales and load response deviation under time-of-use price are both considered. And a load dispatch mode based on the pre-control of the deviation is proposed as well. To realize the potential of cooperatively optimization of the wind power, conventional unit, fast unit, price-based and incentive-based demand response, this paper develops a rolling dispatch model on “day ahead-in day-real time” scales. Case study verifies the effectiveness of the model and solving methods, and also analyzes the way in which the uncertain factors affect the dispatch plan. And the optimal results of the multi-timescale rolling decision on economic operation area are verified as well. Although dispatch plans could be optimized by improving the prediction accuracy, the change laws of uncertain factor deviation on multi-time scales and complementary characteristics of different resources should be considered as well. On condition that reliability constrains are satisfied, the economic operation area of different time scales could be decided by the deviation size of uncertain factors on the same time-scale, thus the cost of the system operation could be reduced. This work is supported by National Natural Science Foundation of China (No. 51777102) and China Southern Power Grid Company “Reserve Capacity Assessment and Planning under Electricity Market Environment”.