Underwater concrete soft mattress

The utility model relates to an underwater concrete soft mattress, and belongs to the field of hydraulic engineering, the underwater concrete soft mattress comprises a connecting rope and a plurality of concrete blocks, the connecting rope comprises a transverse rope and a longitudinal rope, the transverse rope and the longitudinal rope simultaneously penetrate through the single concrete block, the length direction of the transverse rope is perpendicular to that of the longitudinal rope, and a lap joint assembly is arranged in the concrete block. The lap joint assembly is used for connecting the transverse rope and the longitudinal rope. Before concrete pouring is conducted, the transverse ropes and the longitudinal ropes are connected at the staggered positions, in the process of formwork arrangement and later pouring, the state of the connecting ropes in a cavity has higher stability, the relative position of the connecting ropes and concrete blocks also has higher certainty, and when the soft mattress is