In previous researches on the history of sino-foreign trade in the late Ming Dynasty,scholars mainly focused on the famous trade of raw silk .But it has been proved that in the same period,abundant varieties of Chinese silk piece goods as high grade fabric with considerable commercial value gradually became the major goods exported to Japan via Macau,and Portuguese merchants' important source of income as well . Westerners gained their initial knowledge on Chinese silk piece goods in the early 16th century when they first arrived in the East .Thereafter,as Jesuits and other Catholic missionaries gained access to the mainland China,along with the development of sino-foreign trade,Chinese silk piece goods were more and more frequently mentioned in their letters and reports .Those merchants and missionaries even made a detailed description about the way of trade and the export amount which could reach up to thousands of chests .According to some important historical materials (five trade lists),we can get a clear view of some details such as categories and sale prices of Chinese silk piece goods in Macau's export trade in the first half of the 17th century .By comparing it with raw silk and other goods,this paper intends to figure out the actual increase of silk piece goods in specific seasons in order to prove its growing significance in Macau-Japan trade as well as the overall foreign trade in China at that time . Different from raw silk,silk piece goods were of wide varieties and non-standardized shapes with varying length and width .Therefore,in Macau-Japan trade,following the tradition of the Chinese market,silk piece goods were sold at retail by weight according to corresponding qualities,rather than sold in pancada as raw silk . It's worth mentioning that Jesuits started investing in this beneficial trading activity a long time ago . In charge of business activities like a shrewd merchants,procuradors stayed alert to the market and would timely purchase profitable commodities in short supply .Moreover,in Nagasaki and other places they took part in the sales activities organized by Armacao,a kind of commercial organization in Macau . Inevitably,these highly market-oriented commercial activities would result in business risks .However,because of the shortage of missionary funds and the need for social activities,the huge investment in silk piece goods trade between Macau and Japan played an irreplaceable and unique role in the Jesuits' missions .