In this paper, an automatic method for Persian WordNet construction based on Prenceton WordNet 2.1 (PWN) is introduced. The proposed approach uses Persian and English corpora as well as a bilingual dictionary in order to make a mapping between PWN synsets and Persian words. Our method calculates a score for each candidate synset of a given Persian word and for each of its translation, it selects the synset with maximum score as a link to the Persian word. The manual evaluation on selected links proposed by our method on 500 randomly selected Persian words, shows about 76.4% quality respect to precision measure. By augmenting the Persian WordNet with the un-ambiguous words, the total accuracy of automatically extracted Persian WordNet is about 82.6% which outperforms the previously semi-automated generated Persian WordNet by about 12.6%.