The invention relates to a delimiting method of bird-caused damage risk areas of poles and towers of a power transmission line. The delimiting method comprises the following steps of: calculating an electric potential on the power transmission line when bird droppings or bird nest materials drop through numerical simulation of a three-dimensional static electric field finite element method to obtain a voltage between a line conductor and foreign matters, and judging whether breakdown can occur by taking rod-rod air gap power-frequency breakdown voltage data as criteria; and respectively calculating to mark out a range which possibly causes breakdown through changing the lengths and positions of the foreign matters, thereby drawing bird-caused damage risk areas of the poles and towers. The delimiting method of the bird-caused damage risk areas of the poles and towers of the power transmission line can be used for providing reference basis for preventing and controlling bird-caused damages of the poles and towers of the power transmission line and effectively improving the safe and stable operation level of a power grid and is suitable for delimiting of the bird-caused damage risk areas of the pole and towers of the power transmission line.