Larger power of armored vehicle cooling system was focused on. For needs of higher fan speed control and effective energy saving, the basic compositions and principles of armored vehicle hydraulic driven fan system were expounded, and the systematic mathematical model was established. Based on the simulation analysis which carried out on the different performance parameters system, such as motor displacement, the total volume system and so on, the influence laws to the performance parameters of dynamic characteristics of hydraulic drive fan system are introduced, which provide the theoretical guidance for the optimization design of the system.