The characteristics and distribution patterns of light detritus (0.063mm~0.125mm) in bottom sediments represent a significant indicator for the identification of the origin of sediment. Two hundred and nineteen surface sediment samples, which were collected from the Western Philippine Sea, were analysed to identify the light detritus suites and their distributions in the study area. The area can be divided into 3 light detritus provinces: (Ⅰ) Province east of the Philippine Trench. The material provenance of this province mainly is calcareous or siliceous organism, in addition, circumjacent island arc has a contributor to a quantity of volcanogenic detrital components in this region. (Ⅱ)—Middle province, light detritus may mainly originate from seamounts with intermediate—acid volcanic rock, or the product of erupting intermediate—acid volcano. (Ⅲ)— Province west of the Palau—Kyushu Ridge. Material provenance of this province is relatively complicated. A small quantity of feldspar and quartz may be mainly originated from seamounts with intermediate—acid volcanic rock or the product of erupting intermediate—acid volcano, and volcanic scoria mainly originate from volcano erupting on the Palau—Kyushu Ridge. We suggest that, (1) biogenic debris of the study area is closely relate to water depth, and the amount of biogenic debris is mainly controlled by CCD (i.e., Carbonate Compensated Depth). (2) Volcanogenic detritus derived from Luzon island arc, which can be transported short distance by ocean current and wind, have a little contributor to sedimentation in west Philippine basin. The weathering products of volcanic rocks of the submarine plateau (e.g., Benham Plateau) and circumjacent ridges(e.g., Palau—Kyushu Ridge ) has an important contributor to detritus sedimentation in the study area, and the influence scope of them rests on the intensity of submarine weathering. (3)Terrigenous materials from China's mainland and adjacent Philippine island arc have little influence on sedimentation of this study area. The intermediate and acid seamount which maybe exist , may be the main origin of felsic detritus.