The utility model relates to a high-voltage power transmission iron tower with a variable section length, which belongs to the technical field of the transmission and distribution project. The high-voltage power transmission iron tower with the variable section length consists of a tower body with a variable section length, a tower head, tower legs and tower feet. Section lengths in all tower sections are different and oblique angles of web members are equal to or approach to the optimal value of 45 degrees, so that the torsion resistance and bending resistance capacities of the tower body, particularly the tower body at a bottle neck section, can be effectively improved. The high-voltage power transmission iron tower with the variable section length is used for a high-voltage power transmission line.