The invention discloses a ciphertext full-text search system, comprising an original text processing module, a word segmentation module, an encrypting module, a file ciphertext storage module, a ciphertext index module, a ciphertext search module, a search result processing module and a system management module. The system adopts a ciphertext dynamic sequential tree index structure, a word segmentation group technology and a file local ciphertext dynamic sequential tree index updating method, and can realize index establishment, dynamic index updating, full-text search and substring query under a ciphertext state. The system also can realize peer-to-peer full text research for a safety overlay network in a P2P network and introduces an index file carbon copy replication mechanism based ona peer-to-peer network hubs and nodes. In addition, the ciphertext full-text search system has good expandability, solves the problems of distribution storage and search of massive data index files, increased no occupation of network bandwidth, and has high network resource utilization ratio.