The invention relates to a digital model splicing method of an electric power setting calculating system. The digital model splicing method of the electric power setting calculating system is characterized by comprising the following steps of firstly unifying regulations of the whole grid device naming notations; secondly analyzing boundary equivalent data in each level of an power grid initial model; thirdly splitting and removing the boundary equivalent data in each level of the power grid initial model and retaining inner data in the initial model; fourthly merging the data, namely, merging the inner data in one of the power grid initial models and the actual boundary data in the adjacent power grid initial model; and fifthly exporting a splicing result to a setting calculating data center. The digital model splicing method of the electric power setting calculating system has the advantages that integration of setting calculating data and operation management is achieved and basic data unifying, model unifying, regulation unifying, standard unifying and platform unifying are achieved so that the requirements for 'source port maintenance and whole grid sharing' of an intelligent power grid are satisfied, model information setting and sharing among multi-level relay protection are achieved maximally and problems of 'information isolated island' and the like are solved.