The AGROVOC is a multilingual structured thesaurus in the agricultural domain. It has already been mapped with several vocabularies, for example AGROVOC-CAT, AGROVOC-NALT , AGROVOC-SWD. Although these vocabularies already contained a good portion of non-preferred terms, the terms are collected under the literary warrant and institutional warrant principles; which means vocabularies were collected based on the documents and publications rather than user‟s queries. It is still very common that end users would use different terms to express the same concept. In light of above discussion, we need to bridge these vocabularies and the users‟ terms Background