Method and device for expanding query, search engine system

The invention discloses an expansion query method, a device and a search engine system containing the device, which can solve the problems that the natures of relevant query words provided by the existing search engine are same possibly, so the searched results by using the query words are similar and whether more information in a wider range can be searched or not is uncertain. The method comprises following steps: statistics of co-occurrence words with the query words is carried out; all the co-occurrence words are classified; a characteristic word is selected for each type; the characteristic words of various types are taken as the relevant query words of the query words. Compared with the prior art, the invention provides the multi-type query for a user, the natures of various query words are different, thus being capable of querying the more information in the wider range. The expansion query method guides the user to use better words to carry out the retrieval, thus being capable of obtaining better retrieval effect; the quiddity of guiding the user is to carry out the speculation of the query purpose of the user and further carry out the division, thus obtaining better effect.