1. A query transformation system enabling retrieval of multilingual web documents comprising: a query input unit for imputing a query consisting of a source language, the query input unit comprising a keyboard; an input query memory unit for storing the query, consisting of the source language, received from the query input unit; a transformation control unit for controlling the entire query transformation operation of the system; a translation generating/filtering unit for generating translations of the input query and filtering unnecessary ones of the generated translations; a translation knowledge unit stored with at least one electronic dictionary to be used for a transformation of queries and a variety of information; a transformed query memory unit for storing the query transformed from the source language into a target language; and a result output unit for outputting the result of the transformation in the form of the target language on a screen; wherein the translation generating/filtering unit comprises: a translation generator for generating all possible translations of the source language input query by reference to a translation dictionary; a semantic category verifier for receiving the generated translations from the translation generator, a eliminating translations having a low semantic similarity from the received translations, based on a semantic category tree; and a collocation information verifier for receiving the translations, which includes no translation having a low semantic similarity, from the semantic category verifier, and eliminating translations having no collocation from the received translations, based on word collocation information.