A multidimensional evaluation method for a large-scale grounding grid includes the following steps of on-site testing, numerical calculation based on the electromagnetic field principle and multidimensional evaluation on the grounding grid. The foothold of the multidimensional evaluation method for the grounding grid is based on basic functions of the grounding grid, the basic functions are stream breaking and potential holding safety performance under power frequency grounding faults and lightning stroke faults, and the evaluation problems of characteristic parameters reflecting the safety performance of the grounding grid under the power frequency grounding faults and in the state of lightning stroke are mainly solved, wherein the characteristic parameters relate to grounding grid potential rising, potential difference in the grid, a step voltage, a contact voltage and the like. The multidimensional evaluation on the grounding grid is achieved from the aspects of the characteristic parameters of the grounding grid, integrity of the grounding grid, corrosion evaluation, thermal stability check and the like, safety of the grounding grid is expressed more scientifically, the evaluation on the state of the grounding grid is more accurate, and the safety problem and the defects of the grounding grid are rectified more effectively in a more pertinent mode.