Abstract: The exterior walls of a 500 kV substation construction project are made of real stone paint. Conduct quality control over the construction process through QC group activities. In response to the factors of uneven particle size and color difference of exterior wall real stone paint, countermeasures have been formulated following the 5W1H principle. By controlling nozzle pressure, controlling spraying thickness, and selecting spray guns and nozzles reasonably, the one-time optimization rate of exterior wall real stone paint construction was ultimately increased to 96%. The engineering construction goal of safety, reliability, and excellent craftsmanship has been achieved.