The invention discloses a large-scale wind turbine optimal control system provided with a multi-level hierarchical structure, which comprises a data analysis and strategy selection unit on a wind power field grade, wherein, the unit is in charge of processing the function of large information amount demand and complex calculation task, and meanwhile, coordinates the coordination between each wind turbine, leading the whole efficacy of the wind power field to be the best; a coordinating control and fault diagnosis unit on a turbine grade, which is in charge of handling various transaction in the turbine, and meanwhile, coordinates the coordination between each loop in the turbine, leading the whole efficacy of the turbine to be the best and to reasonably and efficiently complete a task assigned to the wind turbine by the data analysis and strategy selection unit on the wind power field grade; and an execution mechanism control unit on a loop grade, which makes specific action request for each loop and guarantees the accurate and exact operation of various execution mechanisms, such as a motor, a pump, a valve, a switch, and the like. The system solves the problem of inadequacy hardware resource utilization, lower information resource utilization ratio, and low coordination degree between each function in a large-scale wind turbine control system.