A method and a device for modifying a Lucene index file are disclosed. After acquiring a target field to be modified, an old term to be modified under the target field and a new term for replacing the old term, every segment in an index folder may be firstly traversed to generate corresponding information of the new term according to corresponding information of the old term and generate a new index file of the segment based on information under other fields of the segment and corresponding information of the new term and corresponding information of other terms under the target field of the segment. Then a corresponding original index file in the index folder is replaced with the new index file, thereby achieving the modification of a specific term under a certain field in the Lucene index file.