The dynastic disorder accompanying the Ming-Qing transition in seventeenth-century China，together with a global economic crisis，stimulated the rise of piratical activity along the Guangdong coast. During the early 1650s，the pirates operated as mostly independent units，some allied with the Ming and others with the Qing. However，over the course of the following decade，the vast majority joined forces with the Zheng family on Taiwan. This paper explores several reasons for this alliance，including the stringent enforced Qing ban on trade and travel abroad，ideological resistance to Manchu rule over China，and Zheng dominance over trade in maritime East Asia. In the long term，the rise of the Cantonese pirates reflected the increasing geopolitical and economic importance of Southeast Asia as a gateway to the Indian Ocean. They played a pioneering role in the settlement of Southeast Asia and the development of its maritime trade.