This paper presents a new approach to improve the word alignment. Building a bilingual dictionary is one of the main applications for word alignment. However, the research of using the bilingual dictionary to improve the word alignment is not enough. There are two bottlenecks. The first is that large bilingual dictionary is hard to get. The second is that the normal approach of using bilingual dictionary does not make full use of the dictionary. We designed a bootstrapping algorithm to conquer the bottlenecks, achieving a good result.