The invention discloses an NLP text security auditing multi-level retrieval system, which utilizes a data structure of a compressed prefix tree to store and search data, is high in query speed, reduces memory occupation by more than two thousands of times compared with a dictionary tree data structure, and improves the retrieval efficiency. The keyword matching sub-module, the sentence similarity matching sub-module and the text classification deep learning sub-module form a hierarchical search structure of three-level search, the query accuracy is high, search of dominant sensitive words can be covered, meanwhile, text content security auditing can be conducted semantically, the accuracy, the error-tolerant rate and the coverage rate are guaranteed, and the search efficiency is improved. The problems that an existing NLP text security auditing system uses a data structure of a Trie tree for storage, the occupied storage space is large, the memory cost of a server is increased, large-scale deployment on the same server is inconvenient, the performance is difficult to achieve optimization, the model generalization ability is limited, and the system reliability is poor are solved. And the prediction accuracy is unstable.