Abstract: The viscous absorption of suspended particulate matter is analyzed,and the parameters of su-spended particulate matter needed in the study of sound propagation in seawater are clarified.Based on theoretical analysis of the viscous absorption of suspended particles,the ranges of the parameters of suspended particles affecting sound propagation in suspended particulate matter seawater are indicated.So the basis is provided for acoustical study to work on sea survey of suspended particulate matter,data accumu-lation and sea area delimitation.