The invention discloses a load reducing system of a wind generator set and a working method of the load reducing system. The system comprises a machine readable storage device, display equipment, a display adapter, input equipment, sensors, a processor, a peripheral interface, a memory and network interface equipment, wherein the machine readable storage device, the display adapter, the input equipment, the sensors, the processor, the peripheral interface, the memory and the network interface equipment are in communication through a bus, the display equipment is in communication with the bus through the display adapter, and the network interface equipment is in communication with remote equipment through a network. The method includes the steps of inputting initial data, collecting parameters of all the sensors, selecting an operating mode and controlling a fan to enter the selected mode. According to the system and the method, various parameters in the operating process of the fan are collected, a variable pitch system, a yaw system, a braking system and the like are integrated, the structural load of the fan is effectively reduced, and the limitation of independent operation of the systems on reduction of the structural load is avoided.