Abstract: Temporary grounding devices are used in outdoor construction of electric power engineering. The grounding resistance value of the current vertical grounding pile is too high, which may lead to electric shock accidents. In this paper, CDEGS simulation calculation software is used to establish the grounding dispersion model of horizontal bare copper stranded grounding conductor, calculate the grounding resistance value and surface potential distribution characteristics of temporary grounding device under different laying lengths and soil resistance conditions, and compare and analyze the grounding dispersion characteristics of horizontal bare copper stranded and common vertical grounding pile. In view of the actual outdoor construction conditions of power engineering, a calculation model for the dispersion of temporary grounding device was established. At the same time, the dispersion characteristics of grounding conductor under the mixed geomorphic condition of cement road surface and soil were calculated. Through the simulation calculation results, proved by single dimension and the structure of vertical grounding pile as the risk of temporary grounding device, combined with the power engineering construction site temporary grounding actual working condition, the installation of temporary grounding device is given advice, related research conclusions can provide reference for substation of power engineering construction safety.