Abstract: Using XRD method, the clay minerals of two Quaternary cores F090815 and F100609 located in Parece Vela Basin, East Philippine Sea were studied in this article. The results show that there are some differences in mineral assemblage between the north and the south. In the southern core F090815 the most abundant content is smectite (50%), then illite (37%), and the lowest is kaolinite and chlorite (13%); however, in the northern core F100609 the most abundant content is illite (47%), then smectite (39%), and the lowest is kaolinite and chlorite (14%). According to contents and characteristic of clay minerals, both the cores F090815 and F100609 can be divided into four parts. According to assemblage characteristic, chemical index and crystallinity of clay minerals, we think that smectites were originated from submarine basalt alteration in the Mariana Trough; while illites were derived mainly from the west continent under strongly physical weathering probabeg associated with the tormation of loess in the East Asia continent, so were kaolinite and chlorite.