Protection device and method for controllable-pitch propeller blade root bolt

The invention relates to a protection device and method for a controllable-pitch propeller blade root bolt. An annular space formed between the head of a blade root bolt and a mounting hole of a bladeflange is filled with a blade root bolt protective agent for guaranteeing the external line type of a blade, external foreign matters can be prevented from entering the annular space area, and a protective layer is formed outside the blade root bolt. The annular space formed by the blade root bolt and the blade flange mounting hole is filled with the blade root bolt protective agent, the externalline type of the blade is guaranteed, external foreign matters are prevented from entering the area, and the protective layer is formed outside the blade root bolt. The protective layer has good insulativity and corrosion resistance, and can effectively reduce the risks of chemical corrosion, electrochemical corrosion and hydrogen embrittlement fracture of the blade root bolt to a certain extent.And meanwhile, while isola