The invention relates to a substation grounding device state evaluation method based on fuzzy comprehensive evaluation, which includes the following steps: (1) building a grounding device state evaluation factor set; (2) introducing degradation degree, and normalizing the evaluation indexes of the grounding device state evaluation factor set; (3) building grounding device state sets; (4) building a membership function, and obtaining the membership degree of each evaluation index to different grounding device state sets; (5) determining the weight of each evaluation index; and (6) building a substation grounding device state evaluation model, and obtaining a final substation grounding device state evaluation result. Compared with the prior art, the method has the advantages of high evaluation accuracy, less calculation, and the like. Under the condition of considering all the characteristics of a grounding device, the state of the grounding device can be evaluated more accurately, and a basis can be provided for the repair and improvement of the substation grounding device.