A method for replacing a tower foot of a transmission tower is characterized in that the method comprises the following specific steps that 1, a supporting device is connected to the position betweenthe tower foot where a to-be-replaced tower foot is located and main iron; 2, a steel wire protective rope is connected to the position between the main iron where the to-be-replaced tower foot is located and the bottom of the supporting device in a fastened mode, and the main iron where the to-be-replaced tower foot is located is supported through the supporting device; 3, a main iron bolt and atower footing bolt which are connected to the to-be-replaced tower foot are disassembled, and the to-be-replaced tower foot is removed; 4, dust on the upper surface of a tower footing where the to-be-replaced tower foot is located is cleaned up, the main iron where the to-be-replaced tower foot is located is subjected to rust removing, and the main iron is coated with anti-rust paint; 5, the new tower foot is installed on the upper surface of the tower footing through the tower footing bolt, and the upper end of the new tower foot is connected to the main iron through the main iron bolt; and 6, the supporting device and the steel wire protective rope which are connected to the position between the tower footing and the main iron are disassembled. According to the method for replacing the tower foot of the transmission tower, the operating strength can be reduced, the construction occupied area is decreased, the labor cost is reduced, electrified replacement is achieved, and normal electricity utilization of enterprises and residents is ensured.