Abstract: This paper proposed sentence similarity computing based on ontology. Using the relations between the ontol- ogy concepts and key words in the sentences to establish semantic index to extract the direct and indirect semantic rela- lion, ontology based semantic vector was represented to calculate the semantic similarity between sentences, thus the sentence similarity computing method was proposed. This method is applied in the Microsoft Research Institute of para- phrase corpus (MSRP). Experiments show that compared with the related similarity computing methods, this method obtains good accuracy and recall rate in the incomplete additional information background.

Key words: Sentence similarity computing, Ontology, WordNet