Abstract: Combined use of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometer (EDX) technology, the structure and composition of suspended particles collected in the spring of 2012 in the muddy area of middle South Yellow Sea were systematically observed. The types, characteristics and spatial distribution of suspended particles in the study area were revealed, and high temperature burning particles were discovered for the first time. The results showed that there were various types of suspended particles in the study area, including detrital mineral, authigenic minerals, bioclasts and high temperature combustion particles, among which the high temperature combustion particles are siliceous or iron regular spherical particles. At the same time, organic coating, mineral floc, mineral-bioclastic floc, mineral-organic coating floc, mineral-bioclastic-organic coating composite floc and other floc particles appeared. The measured results indicated that the particle size ranged from 0 to 500 μm, the main bodies were concentrated between 0 to 20 μm, and the average particle size was 7.84 μm. The particle sizes of different suspension types were significantly different, and their gradations conformed to the logarithmic normal distribution. The suspended particles in this area can be transported in the water bodies in a gradual suspension manner and can remain in water for a long time.