The invention discloses a simulation method for soil structure with the existence of an underground store and an underground parking lot, belongs to the technical field of the safety of substations of electrical power systems, and particularly relates to a novel soil structure model. When the properties of an earthing system of a substation are analyzed, large space regions, such as the underground parking lot and the underground store, existing below the earthing system are regarded as soil regions of which the resistivity is infinitely great; for other uniform soil regions of the earthing system, the resistivity is rho1. The model is simple to use and convenient to operate and realize. After the properties of the earthing system on the basis of the model are analyzed, the analyzed properties and a traditional calculating and analyzing result are compared and calculated to obtain the influences of the large space regions, such as the underground store and the underground parking lot on the properties of the earthing system, and the theory basis for pushing out the subsequent relevant design standard is provided.