The D-type flexible mattress is the main technology of the bottom protection structures in Changjiang waterway remediation engineering.In order to enhance the longitudinal linking strength of D-type flexible mattress,reduce the “tearing” phenomenon and better play the effect of bottom protection and sand fix,this paper conducts the program design of longitudinal linking mode,conducts the test study on the problems concerned,proposes the new longitudinal linking mode,and verifies it through the engineering practice. The result shows that the linking mode of 14 mm polypropylene rope meets the requirement of mattress sinking basically.