1. A system for saving digital content classified by person-based clustering, comprising: a database located on a non-transitory computer readable medium to save a plurality of digital content classified by person-based clustering; a data structure generation unit located on the non-transitory computer readable medium to generate a data structure including a plurality of nodes using the plurality of digital content; a face recognition unit located on the non-transitory computer readable medium to extract a face descriptor of new digital content to be saved in the database; a cluster classification unit located on the non-transitory computer readable medium to classify the new digital content and the plurality of digital content by the person-based clustering using the extracted face descriptor; and a data structure update unit located on the non-transitory computer readable medium to update the data structure according to the classification.