Based on the analysis of application of the D-shaped soft mattress structure in the Yangtze River Waterway Regulation Project for many years,we develop the D-shaped soft mattress structure with unit blocks and study the construction technology of it.This structure is composed of the mattress and ballast,and the concrete block is a circle.The concrete ballasts blocks are tied together by units and bound to form a piece using a polypropylene rope in series during prefabrication.The field tests show that,comparing with the conventional D-shaped soft mattress structure,the D-shaped soft mattress structure with unit blocks is safer in the process of underwater sinking,and raises the terrain’s comprehensive critical slope angle and improves the adaptability of the mattress to the terrain.