Abstract: To understand the distribution characteristics and sedimentological significance of suspended particulate matter (SPM) in the Russian Arctic Seas, the particle concentration, composition, and rock magnetism of SPM samples collected in the surface seawater of the Kara Sea-Laptev Sea-Eastern Siberia Sea during the Sino-Russian joint Arctic expedition (AMK78 voyage) were analyzed. Results show that the SPM was mainly composed of terrigenous detritus and siliceous plankton debris. The SPM concentration was the highest in the Dmitry Laptev Strait and its eastern sea areas, followed by the outer sides of the Ob and Yenisei estuaries, and were generally lower in the other sea areas. The magnetic minerals in the SPM were single-domain and multi-domain magnetite. The terrigenous detritus was concentrated in the waters near the coast and the estuary of the river, and the proportion of siliceous bioclasts in the SPM in the sea farther from the coast and the estuary increases. The SPM concentration was mainly affected by the flux of terrigenous debris transported into the sea by rivers and coastal erosion, while the magnetic minerals in SPM were related to the rock types in the watershed and were affected by the Siberian Coastal Current. Coarse magnetic minerals were distributed in the coastal areas, which might be related to coastal erosion.