The invention discloses a method of two-dimensional digital core storage applied to reconstruction of core images with different granularities. The method comprises the steps that relevant storage parameters are obtained according to a storage format of two-dimensional digital core data; quad-tree cutting parameters are determined; based on the storage parameters and the quad-tree cutting parameters, the two-dimensional digital core data is cut, and each non-blank leaf node sub-block obtained by cutting is stored; and the leaf node sub-blocks are combined, parent node sub-blocks of the blocks are obtained, combination of the parent node sub-blocks is continued till root node blocks of the quad-tree are obtained, and each non-blank parent node sub-block obtained through combination and the root node blocks are stored separately. The method has the advantages that data with the different granularities is generated; the images with the different granularities are displayed; and image display is accelerated.