The present invention discloses a system for identifying, associating, searching and presenting documents based on relation combination, which builds a computer system-based knowledge management system in a professional field and improves the learning efficiency and utilization of professional knowledge. The technical solution includes finding a series of documents having an inter-document logical relationship with a group of specific keywords from massive documents in a keyword search manner, and naming a relation graph among the specific series of documents with a group of keywords strongly correlated therewith; combining, into one set, a plurality of inter-document relation graphs of which the names have a group of like term keywords and which have specific logical relationships among one another, and naming the same with the group of like term keywords in a certain logic order. On this basis, the inter-document relation graphs mentioned above are presented from multiple perspectives and in multiple layers by means of graphicalization and a set sequence based on a specific logical relationship in a manner complying with the logic of human brain thinking process.