Abstract: This paper proposed a rules-based method for recognizing and transforming the element sub-sentences to improve the translation quality of them in patent machine translation．By analyzing the format of Chinese element sub-sentences,we extracted the description features,and created the recognition rules based on that．By comparing Chinese and English element sub-sentences,we summarized the differences between them,and created the transformation rules based on that．At last,we applied the rules to an existing MT system．Experiment shows that the method can recognize and transform element sub-sentences,and then improve their translation quality in patent machine translation.

Key words: Element sub-sentences,Recognize,Transform,Machine translation,Patent