The present invention relates to a query completion method in a 
community ask-answer search, and belongs to the technical field of 
information retrieval. The method comprises the following steps: step 1: building a cQA 
database; step 2: building an entity dictionary and a 
phrase dictionary; step 3: for a 
query statement input by a user, determining whether the last word is complete, and if not, performing completion on the last word; step 4: for the 
query statement, sorting questions in the 
database by using a sorting function, to obtain a 
list of initial candidate questions; step 5: screening the 
list according to requirements on 
divergence, size, local rank preservation and fidelity ; step 6: performing sorting again according to importance and quality of the candidate problems; and step 7: outputting the first N candidate problems after the sorting is performed again, for the user to select. Compared with the prior art, according to the query completion method in a 
community ask-answer search provided by the present invention, query completion can be achieved in 
spite of lack of a user search log, thereby solving the problems in the prior art such as similar problem recommendation, an improper size, unchanged relative order and 
distortion; and the user experience is better than that of an existing 
search engine.