The utility model relates to a special exposure testing frame for a steel structure of an electrical power system, aiming at monitoring on corrosive condition of structural materials, equipment and materials in a high voltage highfield environment for power transmission and transformation of the electrical power system. The special exposure testing frame comprises a supporting frame and an exposure frame, wherein the exposure frame is installed on the supporting frame by being formed with a 45-degree include angle with the ground. The supporting frame is provided with a vertical bracket and a vertical bracket adjusting device. The exposure frame is provided with a cross beam, and a test sample is fixedly arranged on the cross beam through a fixture. The testing frame provided by the utility model is fixedly installed by the steel structure, and the atmosphere exposure frame is not fixed on the ground but fixed on the steel structure of a power transmission and transformation device with adjustable height. Atmosphere corrosive speed of the materials at different heights and different positions under different electric field intensities can be monitored by way of hanging pieces. Samples can be directly hung on the power transmission and transformation device, so that corrosive condition of the materials can be directly monitored for transformer substations, transmission towers and other power transmission and transformation devices.