The Ming maritime prohibition policy had a negative influence on commercial activities along the Chinese coasts. However，in order to show its priorities and generosity，Ming specially permitted Koreans to conduct trade in China. There resulted two kinds of trade by Korean embassies in China：tributary trade and private trade. Former scholars have analyzed well on the tributary trade，but few people pay attention to the private or smuggling trade. When Korean tributary envoys went to China，they always carried private cargo，such as cloth，horses，gold，silver，marine products and handicraft articles，and traded with the Chinese in the capital，in Liaodong and Shandong. Koreans mainly purchased Chinese medicine，silk，books，water buffalo horns，lead，iron and copperas. These products were mainly consumed by the Korean court and aristocrats，and to a lesser degree used by the common people. Although the Korean government issued decrees to prohibit private trade many times，they had little effect because these embassies could make huge profits from the trade and Koreans needed Chinese commodities badly.