Abstract: 53 samples of surficial suspended particulates have been collected in the Prydz Bay by the 29th China Antarctic scientific expedition. The compositions of surficial suspended particles are measured with the scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). The types and distributions of both the single particles and aggregates in the surficial suspended particles are analyzed and their controlling factors discussed. The results show that the concentration of summer surficial suspended particles range from 0.08 to 1.66 mg/L, with an average of 0.43 mg/L in the Prydz Bay, of which the high value is distributed mainly in the near-shore area. The biological particles dominate and are high in both the southeastern near-shore area and the northwestern deep-water area. Mineral particles are relatively low and the content of other particles was between the two groups of particles. The average content of aggregate is about 10% in all the surficial suspended particles. The types of aggregates of surficial suspended particles include diatom aggregate, mini-type algae aggregate, mineral aggregate, organic film and miscellaneous aggregates, etc. The controlling factors of the distributions and compositions of surficial suspended particles in the Prydz Bay include marine topography, marine currents system and the terrigenous materials supply. Suspension flocculation processes mainly involve extracellular polymeric substances (EPS), transparent exopolymer particles (TEP) and marine snow. The flocculation of suspended particles accelerates the sinking of suspended particles and plays a very important role in the depositional process.