Abstract: Organophosphorus pesticides (OPPs) of composition and distribution characteristics in the sea waters of Sanggou Bay have been studied by Gas Chromatography-Mass Spectrometry (GC-MS). Eight OPPs in the seawaters of Sanggou Bay were determined by using GC-MS with the external standard quantitative method in the Spring and Autumn of 2009. The range of concentration of ∑OPPs in the bay was 0.001-0.265 μg/L with an average of 0.061 μg/L. Six different types of OPPs were detected with the main pollutants being malathion and parathion. The distribution of OPPs from the survey in Sanggou Bay are presented in this paper. The results show that the concentration of OPPs is higher in the centre, lower far from the shore and decreasing from the outside to the inside of the bay at the surface water body, with the highest concentration at the bottom water body near the mouth of the bay in Spring. The concentration of OPPs increases from northwest and northeast outside of the bay to inside at the surface water body and increases from inside to outside at the bottom water body in Autumn. The results provide some references for the distribution characteristics of OPPs in this region.