This paper implements and compares three different strategies to use english as pivot language for chinese-japanese patent translation: corpus enrichment,sentence pivot translation and phrase pivot translation. our results show that both corpus encrichment and phrase pivot translation strategy outperfrom the baseline system, while the sentence pivot translation strategy failed to improve the system. we apply the strategies on large data set and figure out approaches to improve effieciency. finally, we perfrom minimum bayes risk system combination on the different results of direct translation system and pivot translation systems, which significantly outperforms the direct translation system by 4.25 BLEU scores.